diff --git a/csi.c b/csi.c
index 647d5052..4b545d31 100644
--- a/csi.c
+++ b/csi.c
@@ -10,7 +10,7 @@
 #endif
 
 #define LOG_MODULE "csi"
-#define LOG_ENABLE_DBG 1
+#define LOG_ENABLE_DBG 0
 #include "log.h"
 #include "grid.h"
 
@@ -57,10 +57,6 @@ initialize_colors256(void)
                     b * 51 / 255.0,
                     1.0,
                 };
-#if 0
-                colors256[16 + r * 6 * 6 + g * 6 + b] =
-                    (51 * r) << 24 | (51 * g) << 16 | (51 * b) << 8 | 0xff;
-#endif
             }
         }
     }
@@ -72,7 +68,6 @@ initialize_colors256(void)
             i * 11 / 255.0,
             1.0
         };
-            //(11 * i) << 24 | (11 * i) << 16 | (11 * i) << 8 | 0xff;
     }
 }
 
@@ -280,7 +275,7 @@ csi_dispatch(struct terminal *term, uint8_t final)
                       i == term->vt.params.idx - 1 ? "" : ";");
     }
 
-    c += snprintf(&log[c], sizeof(log) - c, "%c (%zu parameters)",
+    c += snprintf(&log[c], sizeof(log) - c, "%c (%d parameters)",
                   final, term->vt.params.idx);
     LOG_DBG("%s", log);
 #endif
@@ -292,11 +287,7 @@ csi_dispatch(struct terminal *term, uint8_t final)
 
         case 'd': {
             /* VPA - vertical line position absolute */
-            int row = param_get(term, 0, 1);
-
-            if (row > term->rows)
-                row = term->rows;
-
+            int row = min(param_get(term, 0, 1), term->rows);
             term_cursor_to(term, row - 1, term->cursor.col);
             break;
         }
@@ -323,25 +314,15 @@ csi_dispatch(struct terminal *term, uint8_t final)
 
         case 'G': {
             /* Cursor horizontal absolute */
-            int col = param_get(term, 0, 1);
-
-            if (col > term->cols)
-                col = term->cols;
-
-            term_cursor_to(term, term->cursor.row, col);
+            int col = min(param_get(term, 0, 1), term->cols);
+            term_cursor_to(term, term->cursor.row, col - 1);
             break;
         }
 
         case 'H': {
             /* Move cursor */
-            int row = param_get(term, 0, 1);
-            int col = param_get(term, 1, 1);
-
-            if (row > term->rows)
-                row = term->rows;
-            if (col > term->cols)
-                col = term->cols;
-
+            int row = min(param_get(term, 0, 1), term->rows);
+            int col = min(param_get(term, 1, 1), term->cols);
             term_cursor_to(term, row - 1, col - 1);
             break;
         }
@@ -452,27 +433,49 @@ csi_dispatch(struct terminal *term, uint8_t final)
 
         case 'P': {
             /* DCH: Delete character */
-            int count = param_get(term, 0, 1);
 
-            /* Only delete up to the right margin */
-            const int max_end = term_cursor_linear(
-                term, term->cursor.row, term->cols);
+            /* Number of characters to delete */
+            int count = min(
+                param_get(term, 0, 1), term->cols - term->cursor.col);
 
-            int start = term->cursor.linear;
-            int end = min(start + count, max_end);
+            /* Number of characters left after deletion (on current line) */
+            int remaining = term->cols - (term->cursor.col + count);
 
-            /* Erase the requested number of characters */
-            term_erase(term, start, end);
-
-            /* Move remaining (up til the right margin) characters */
-            int remaining = max_end - end;
-            memmove(&term->grid->cells[start],
-                    &term->grid->cells[end],
-                    remaining * sizeof(term->grid->cells[0]));
+            /* 'Delete' characters by moving the remaining ones */
+            memmove(&term->grid->cur_line[term->cursor.col],
+                    &term->grid->cur_line[term->cursor.col + count],
+                    remaining * sizeof(term->grid->cur_line[0]));
             term_damage_update(term, term->cursor.linear, remaining);
+
+            /* Erase the remainder of the line */
+            term_erase(
+                term, term->cursor.linear + remaining,
+                term->cursor.linear + remaining + count);
             break;
         }
 
+        case 'X': {
+            /* Erase chars */
+            int count = min(
+                param_get(term, 0, 1), term->cols - term->cursor.col);
+
+            memset(&term->grid->cur_line[term->cursor.col],
+                   0, count * sizeof(term->grid->cur_line[0]));
+            term_damage_erase(term, term->cursor.linear, count);
+            break;
+        }
+
+        case 'h':
+            /* smir - insert mode enable */
+            assert(false && "untested");
+            term->insert_mode = true;
+            break;
+
+        case 'l':
+            /* rmir - insert mode disable */
+            term->insert_mode = false;
+            break;
+
         case 'r': {
             int start = param_get(term, 0, 1);
             int end = param_get(term, 1, term->rows);
@@ -481,9 +484,11 @@ csi_dispatch(struct terminal *term, uint8_t final)
             term->scroll_region.start = start - 1;
             term->scroll_region.end = end;
 
-            LOG_INFO("scroll region: %d-%d",
-                     term->scroll_region.start,
-                     term->scroll_region.end);
+            term_cursor_to(term, start - 1, 0);
+
+            LOG_DBG("scroll region: %d-%d",
+                    term->scroll_region.start,
+                    term->scroll_region.end);
             break;
         }
 
@@ -560,12 +565,16 @@ csi_dispatch(struct terminal *term, uint8_t final)
                     LOG_WARN("unimplemented: flash");
                     break;
 
+                case 7:
+                    term->auto_margin = true;
+                    break;
+
                 case 12:
                     LOG_WARN("unimplemented: cursor blinking");
                     break;
 
                 case 25:
-                    LOG_WARN("unimplemented: civis");
+                    term->hide_cursor = false;
                     break;
 
                 case 1000:
@@ -576,15 +585,28 @@ csi_dispatch(struct terminal *term, uint8_t final)
                     LOG_WARN("unimplemented: report cell mouse motion");
                     break;
 
+                case 1005:
+                    LOG_WARN("unimplemented: UTF-8 mouse");
+                    break;
+
                 case 1006:
                     LOG_WARN("unimplemented: SGR mouse");
                     break;
 
+                case 1015:
+                    LOG_WARN("unimplemented: URXVT mosue");
+                    break;
+
                 case 1049:
                     if (term->grid != &term->alt) {
                         term->grid = &term->alt;
                         term->saved_cursor = term->cursor;
-                        term_damage_all(term);
+
+                        term_cursor_to(term, term->cursor.row, term->cursor.col);
+
+                        tll_free(term->alt.damage);
+                        tll_free(term->alt.scroll_damage);
+                        term_erase(term, 0, term->rows * term->cols);
                     }
                     break;
 
@@ -613,12 +635,16 @@ csi_dispatch(struct terminal *term, uint8_t final)
                     LOG_WARN("unimplemented: flash");
                     break;
 
+                case 7:
+                    term->auto_margin = false;
+                    break;
+
                 case 12:
                     LOG_WARN("unimplemented: cursor blinking");
                     break;
 
                 case 25:
-                    LOG_WARN("unimplemented: civis");
+                    term->hide_cursor = true;
                     break;
 
                 case 1000:
@@ -629,19 +655,27 @@ csi_dispatch(struct terminal *term, uint8_t final)
                     LOG_WARN("unimplemented: report cell mouse motion");
                     break;
 
+                case 1005:
+                    LOG_WARN("unimplemented: UTF-8 mouse");
+                    break;
+
                 case 1006:
                     LOG_WARN("unimplemented: SGR mouse");
                     break;
 
+                case 1015:
+                    LOG_WARN("unimplemented: URXVT mosue");
+                    break;
+
                 case 1049:
                     if (term->grid == &term->alt) {
                         term->grid = &term->normal;
 
                         term->cursor = term->saved_cursor;
+                        term_cursor_to(term, term->cursor.row, term->cursor.col);
 
-                        /* Should these be restored from saved values? */
-                        term->scroll_region.start = 0;
-                        term->scroll_region.end = term->rows;
+                        tll_free(term->alt.damage);
+                        tll_free(term->alt.scroll_damage);
 
                         term_damage_all(term);
                     }
@@ -661,8 +695,40 @@ csi_dispatch(struct terminal *term, uint8_t final)
             break;
         }
 
+        case 's':
+            for (size_t i = 0; i < term->vt.params.idx; i++) {
+                switch (term->vt.params.v[i].value) {
+                case 1001:  /* save old highlight mouse tracking mode? */
+                    LOG_WARN(
+                        "unimplemented: CSI ?1001s "
+                        "(save 'highlight mouse tracking' mode)");
+                    break;
+
+                default:
+                    LOG_ERR("unimplemented: CSI ?%ds", term->vt.params.v[i].value);
+                    abort();
+                }
+            }
+            break;
+
+        case 'r':
+            for (size_t i = 0; i < term->vt.params.idx; i++) {
+                switch (term->vt.params.v[i].value) {
+                case 1001:  /* restore old highlight mouse tracking mode? */
+                    LOG_WARN(
+                        "unimplemented: CSI ?1001r "
+                        "(restore 'highlight mouse tracking' mode)");
+                    break;
+
+                default:
+                    LOG_ERR("unimplemented: CSI ?%dr", term->vt.params.v[i].value);
+                    abort();
+                }
+            }
+            break;
+
         default:
-            LOG_ERR("CSI: intermediate '?': unimplemented final: %c", final);
+            LOG_ERR("unimplemented: CSI: ?%c", final);
             abort();
         }
 
diff --git a/grid.c b/grid.c
index 67f6e57a..178883e4 100644
--- a/grid.c
+++ b/grid.c
@@ -4,5 +4,75 @@
 #include <assert.h>
 
 #define LOG_MODULE "grid"
-#define LOG_ENABLE_DBG 1
+#define LOG_ENABLE_DBG 0
 #include "log.h"
+
+struct cell *
+grid_get_range(struct grid *grid, int start, int *length)
+{
+#define min(x, y) ((x) < (y) ? (x) : (y))
+    assert(*length <= grid->size);
+
+    int real_start = (grid->offset + start) % grid->size;
+    if (real_start < 0)
+        real_start += grid->size;
+    assert(real_start >= 0);
+    assert(real_start < grid->size);
+
+    *length = min(*length, grid->size - real_start);
+    assert(real_start + *length <= grid->size);
+
+    return &grid->cells[real_start];
+#undef min
+}
+
+void
+grid_memset(struct grid *grid, int start, int c, int length)
+{
+    int left = length;
+    while (left > 0) {
+        int count = left;
+        struct cell *cells = grid_get_range(grid, start, &count);
+
+        assert(count > 0);
+        assert(count <= left);
+
+        memset(cells, c, count * sizeof(cells[0]));
+
+        left -= count;
+        start += count;
+    }
+}
+
+void
+grid_memmove(struct grid *grid, int dst, int src, int length)
+{
+    int left = length;
+    int copy_idx = 0;
+    struct cell copy[left];
+
+    while (left > 0) {
+        int count = left;
+        struct cell *src_cells = grid_get_range(grid, src, &count);
+
+        memcpy(&copy[copy_idx], src_cells, count * sizeof(copy[0]));
+
+        left -= count;
+        src += count;
+        copy_idx += count;
+    }
+
+    left = length;
+    copy_idx = 0;
+
+    while (left > 0) {
+        int count = left;
+        struct cell *dst_cells = grid_get_range(grid, dst, &count);
+
+        memcpy(dst_cells, &copy[copy_idx], count * sizeof(copy[0]));
+
+        left -= count;
+        dst += count;
+        copy_idx += count;
+    }
+}
diff --git a/grid.h b/grid.h
index 580ef343..59d9e58b 100644
--- a/grid.h
+++ b/grid.h
@@ -1,3 +1,8 @@
 #pragma once
 
+#include <stddef.h>
 #include "terminal.h"
+
+struct cell *grid_get_range(struct grid *grid, int start, int *length);
+void grid_memset(struct grid *grid, int start, int c, int length);
+void grid_memmove(struct grid *grid, int dst, int src, int length);
diff --git a/input.c b/input.c
index 5e61d49b..319de914 100644
--- a/input.c
+++ b/input.c
@@ -10,7 +10,7 @@
 #include <xkbcommon/xkbcommon-keysyms.h>
 
 #define LOG_MODULE "input"
-#define LOG_ENABLE_DBG 1
+#define LOG_ENABLE_DBG 0
 #include "log.h"
 #include "terminal.h"
 
diff --git a/main.c b/main.c
index f4f9eaa7..a87598c4 100644
--- a/main.c
+++ b/main.c
@@ -6,7 +6,9 @@
 #include <assert.h>
 #include <fcntl.h>
 #include <locale.h>
+#include <getopt.h>
 #include <poll.h>
+#include <errno.h>
 
 #include <sys/ioctl.h>
 //#include <termios.h>
@@ -15,7 +17,7 @@
 #include <xdg-shell.h>
 
 #define LOG_MODULE "main"
-#define LOG_ENABLE_DBG 1
+#define LOG_ENABLE_DBG 0
 #include "log.h"
 
 #include "font.h"
@@ -48,7 +50,7 @@ struct wayland {
 struct context {
     bool quit;
 
-    cairo_scaled_font_t *fonts[8];
+    cairo_scaled_font_t *fonts[4];
     cairo_font_extents_t fextents;
 
     int width;
@@ -61,7 +63,6 @@ struct context {
     bool frame_is_scheduled;
 };
 
-
 static void frame_callback(
     void *data, struct wl_callback *wl_callback, uint32_t callback_data);
 
@@ -76,27 +77,66 @@ attrs_to_font(struct context *c, const struct attributes *attrs)
     return c->fonts[idx];
 }
 
+struct glyph_sequence {
+    cairo_glyph_t glyphs[10000];
+    cairo_glyph_t *g;
+    int count;
+
+    struct attributes attrs;
+    struct rgba foreground;
+};
+
 static void
 grid_render_update(struct context *c, struct buffer *buf, const struct damage *dmg)
 {
-    LOG_DBG("damage: UPDATE: %d -> %d",
-            dmg->range.start, dmg->range.start + dmg->range.length);
+    LOG_DBG("damage: UPDATE: %d -> %d (offset = %d)",
+            (dmg->range.start - c->term.grid->offset) % c->term.grid->size,
+            (dmg->range.start - c->term.grid->offset) % c->term.grid->size + dmg->range.length,
+        c->term.grid->offset);
+
+    int start = dmg->range.start;
+    int length = dmg->range.length;
+
+    if (start < c->term.grid->offset) {
+        int end = start + length;
+        if (end >= c->term.grid->offset) {
+            start = c->term.grid->offset;
+            length = end - start;
+        } else
+            return;
+    }
 
     const int cols = c->term.cols;
 
-    for (int linear_cursor = dmg->range.start,
-             row = dmg->range.start / cols,
-             col = dmg->range.start % cols;
-         linear_cursor < dmg->range.start + dmg->range.length;
+    struct glyph_sequence gseq = {.g = gseq.glyphs};
+
+    for (int linear_cursor = start,
+             row = ((start - c->term.grid->offset) % c->term.grid->size) / cols,
+             col = ((start - c->term.grid->offset) % c->term.grid->size) % cols;
+         linear_cursor < start + length;
          linear_cursor++,
-             //col = (col + 1) % cols,
              col = col + 1 >= c->term.cols ? 0 : col + 1,
              row += col == 0 ? 1 : 0)
     {
-        //LOG_DBG("UPDATE: %d (%dx%d)", linear_cursor, row, col);
 
-        const struct cell *cell = &c->term.grid->cells[linear_cursor];
-        bool has_cursor = c->term.cursor.linear == linear_cursor;
+        assert(row >= 0);
+        assert(row < c->term.rows);
+        assert(col >= 0);
+        assert(col < c->term.cols);
+
+        int cell_idx = linear_cursor % c->term.grid->size;
+        if (cell_idx < 0)
+            cell_idx += c->term.grid->size;
+
+        assert(cell_idx >= 0);
+        assert(cell_idx < c->term.rows * c->term.cols);
+
+        const struct cell *cell = &c->term.grid->cells[cell_idx];
+
+        /* Cursor here? */
+        bool has_cursor
+            = (!c->term.hide_cursor &&
+               (c->term.cursor.linear == linear_cursor - c->term.grid->offset));
 
         int x = col * c->term.cell_width;
         int y = row * c->term.cell_height;
@@ -120,15 +160,9 @@ grid_render_update(struct context *c, struct buffer *buf, const struct damage *d
             background = swap;
         }
 
-        //LOG_DBG("cell %dx%d dirty: c=0x%02x (%c)",
-        //        row, col, cell->c[0], cell->c[0]);
-
-        cairo_scaled_font_t *font = attrs_to_font(c, &cell->attrs);
-        cairo_set_scaled_font(buf->cairo, font);
+        /* Background */
         cairo_set_source_rgba(
             buf->cairo, background.r, background.g, background.b, background.a);
-
-        /* Background */
         cairo_rectangle(buf->cairo, x, y, width, height);
         cairo_fill(buf->cairo);
 
@@ -138,37 +172,75 @@ grid_render_update(struct context *c, struct buffer *buf, const struct damage *d
         if (cell->attrs.conceal)
             continue;
 
-        cairo_glyph_t *glyphs = NULL;
-        int num_glyphs = 0;
+        /*
+         * cairo_show_glyphs() apparently works *much* faster when
+         * called once with a large array of glyphs, compared to
+         * multiple calls with a single glyph.
+         *
+         * So, collect glyphs until cell attributes change, then we
+         * 'flush' (render) the glyphs.
+         */
 
-        cairo_status_t status = cairo_scaled_font_text_to_glyphs(
-            font, x, y + c->fextents.ascent,
-            cell->c, strlen(cell->c), &glyphs, &num_glyphs,
-            NULL, NULL, NULL);
+        if (memcmp(&cell->attrs, &gseq.attrs, sizeof(cell->attrs)) != 0 ||
+            gseq.count >= sizeof(gseq.glyphs) / sizeof(gseq.glyphs[0]) - 10 ||
+            memcmp(&gseq.foreground, &foreground, sizeof(foreground)) != 0)
+        {
+            if (gseq.count >= sizeof(gseq.glyphs) / sizeof(gseq.glyphs[0]) - 10)
+                LOG_WARN("hit glyph limit");
+            cairo_set_scaled_font(buf->cairo, attrs_to_font(c, &gseq.attrs));
+            cairo_set_source_rgba(
+                buf->cairo, gseq.foreground.r, gseq.foreground.g,
+                gseq.foreground.b, gseq.foreground.a);
 
-        if (status != CAIRO_STATUS_SUCCESS) {
-            if (glyphs != NULL)
-                cairo_glyph_free(glyphs);
-            continue;
+            cairo_set_operator(buf->cairo, CAIRO_OPERATOR_OVER);
+            cairo_show_glyphs(buf->cairo, gseq.glyphs, gseq.count);
+
+            gseq.g = gseq.glyphs;
+            gseq.count = 0;
+            gseq.attrs = cell->attrs;
+            gseq.foreground = foreground;
         }
 
+        int new_glyphs
+            = sizeof(gseq.glyphs) / sizeof(gseq.glyphs[0]) - gseq.count;
+
+        cairo_status_t status = cairo_scaled_font_text_to_glyphs(
+            attrs_to_font(c, &cell->attrs), x, y + c->fextents.ascent,
+            cell->c, strlen(cell->c), &gseq.g, &new_glyphs,
+            NULL, NULL, NULL);
+
+        if (status != CAIRO_STATUS_SUCCESS)
+            continue;
+
+        gseq.g += new_glyphs;
+        gseq.count += new_glyphs;
+        assert(gseq.count <= sizeof(gseq.glyphs) / sizeof(gseq.glyphs[0]));
+    }
+
+    if (gseq.count > 0) {
+        cairo_set_scaled_font(buf->cairo, attrs_to_font(c, &gseq.attrs));
         cairo_set_source_rgba(
-            buf->cairo, foreground.r, foreground.g, foreground.b, foreground.a);
-        cairo_show_glyphs(buf->cairo, glyphs, num_glyphs);
-        cairo_glyph_free(glyphs);
+            buf->cairo, gseq.foreground.r, gseq.foreground.g,
+            gseq.foreground.b, gseq.foreground.a);
+        cairo_set_operator(buf->cairo, CAIRO_OPERATOR_OVER);
+        cairo_show_glyphs(buf->cairo, gseq.glyphs, gseq.count);
     }
 
     wl_surface_damage_buffer(
         c->wl.surface,
-        0, (dmg->range.start / cols) * c->term.cell_height,
+        0, ((dmg->range.start - c->term.grid->offset) / cols) * c->term.cell_height,
         buf->width, (dmg->range.length + cols - 1) / cols * c->term.cell_height);
 }
 
 static void
 grid_render_erase(struct context *c, struct buffer *buf, const struct damage *dmg)
 {
-    LOG_DBG("damage: ERASE: %d -> %d",
-            dmg->range.start, dmg->range.start + dmg->range.length);
+    LOG_DBG("damage: ERASE: %d -> %d (offset = %d)",
+            (dmg->range.start - c->term.grid->offset) % c->term.grid->size,
+            (dmg->range.start - c->term.grid->offset) % c->term.grid->size + dmg->range.length,
+            c->term.grid->offset);
+
+    assert(dmg->range.start >= c->term.grid->offset);
 
     cairo_set_source_rgba(
         buf->cairo, default_background.r, default_background.g,
@@ -176,7 +248,7 @@ grid_render_erase(struct context *c, struct buffer *buf, const struct damage *dm
 
     const int cols = c->term.cols;
 
-    int start = dmg->range.start;
+    int start = (dmg->range.start - c->term.grid->offset) % c->term.grid->size;
     int left = dmg->range.length;
 
     int row = start / cols;
@@ -238,17 +310,6 @@ grid_render_erase(struct context *c, struct buffer *buf, const struct damage *dm
         cairo_fill(buf->cairo);
         wl_surface_damage_buffer(c->wl.surface, x, y, width, height);
     }
-
-    /* Redraw cursor, if it's inside the erased range */
-    if (c->term.cursor.linear >= dmg->range.start &&
-        c->term.cursor.linear < dmg->range.start + dmg->range.length)
-    {
-        grid_render_update(
-            c, buf,
-            &(struct damage){
-                .type = DAMAGE_UPDATE,
-                .range = {.start = c->term.cursor.linear, .length = 1}});
-    }
 }
 
 static void
@@ -284,7 +345,7 @@ grid_render_scroll(struct context *c, struct buffer *buf,
     struct damage erase = {
         .type = DAMAGE_ERASE,
         .range = {
-            .start = max(dmg->scroll.region.end - dmg->scroll.lines,
+            .start = c->term.grid->offset + max(dmg->scroll.region.end - dmg->scroll.lines,
                          dmg->scroll.region.start) * cols,
             .length = min(dmg->scroll.region.end - dmg->scroll.region.start,
                           dmg->scroll.lines) * cols,
@@ -326,7 +387,7 @@ grid_render_scroll_reverse(struct context *c, struct buffer *buf,
     struct damage erase = {
         .type = DAMAGE_ERASE,
         .range = {
-            .start = dmg->scroll.region.start * cols,
+            .start = c->term.grid->offset + dmg->scroll.region.start * cols,
             .length = min(dmg->scroll.region.end - dmg->scroll.region.start,
                           dmg->scroll.lines) * cols,
         },
@@ -337,8 +398,11 @@ grid_render_scroll_reverse(struct context *c, struct buffer *buf,
 static void
 grid_render(struct context *c)
 {
+    static int last_cursor;
+
     if (tll_length(c->term.grid->damage) == 0 &&
-        tll_length(c->term.grid->scroll_damage) == 0)
+        tll_length(c->term.grid->scroll_damage) == 0 &&
+        last_cursor == c->term.grid->offset + c->term.cursor.linear)
     {
         return;
     }
@@ -347,9 +411,15 @@ grid_render(struct context *c)
     assert(c->height > 0);
 
     struct buffer *buf = shm_get_buffer(c->wl.shm, c->width, c->height);
-
     cairo_set_operator(buf->cairo, CAIRO_OPERATOR_SOURCE);
 
+    static struct buffer *last_buf = NULL;
+    if (last_buf != buf) {
+        if (last_buf != NULL)
+            LOG_WARN("new buffer");
+        last_buf = buf;
+    }
+
     tll_foreach(c->term.grid->scroll_damage, it) {
         switch (it->item.type) {
         case DAMAGE_SCROLL:
@@ -383,6 +453,28 @@ grid_render(struct context *c)
         tll_remove(c->term.grid->damage, it);
     }
 
+    /* TODO: break out to function */
+    /* Re-render last cursor cell and current cursor cell */
+    /* Make sure previous cursor is refreshed (to avoid "ghost" cursors) */
+    if (last_cursor != c->term.cursor.linear) {
+        struct damage prev_cursor = {
+            .type = DAMAGE_UPDATE,
+            .range = {.start = last_cursor, .length = 1},
+        };
+        grid_render_update(c, buf, &prev_cursor);
+    }
+
+    struct damage cursor = {
+        .type = DAMAGE_UPDATE,
+        .range = {.start = c->term.grid->offset + c->term.cursor.linear, .length = 1},
+    };
+    grid_render_update(c, buf, &cursor);
+    last_cursor = c->term.grid->offset + c->term.cursor.linear;
+
+    c->term.grid->offset %= c->term.grid->size;
+    if (c->term.grid->offset < 0)
+        c->term.grid->offset += c->term.grid->size;
+
     //cairo_surface_flush(buf->cairo_surface);
     wl_surface_attach(c->wl.surface, buf->wl_buf, 0, 0);
 
@@ -416,8 +508,6 @@ resize(struct context *c, int width, int height)
     const size_t normal_old_size = c->term.normal.size;
     const size_t alt_old_size = c->term.alt.size;
 
-    c->term.cell_width = (int)ceil(c->fextents.max_x_advance);
-    c->term.cell_height = (int)ceil(c->fextents.height);
     c->term.cols = c->width / c->term.cell_width;
     c->term.rows = c->height / c->term.cell_height;
 
@@ -426,10 +516,10 @@ resize(struct context *c, int width, int height)
 
     c->term.normal.cells = realloc(
         c->term.normal.cells,
-        c->term.cols * c->term.rows * sizeof(c->term.normal.cells[0]));
+        c->term.normal.size * sizeof(c->term.normal.cells[0]));
     c->term.alt.cells = realloc(
         c->term.alt.cells,
-        c->term.cols * c->term.rows * sizeof(c->term.alt.cells[0]));
+        c->term.alt.size * sizeof(c->term.alt.cells[0]));
 
     for (size_t i = normal_old_size; i < c->term.normal.size; i++) {
         c->term.normal.cells[i] = (struct cell){
@@ -445,13 +535,13 @@ resize(struct context *c, int width, int height)
         };
     }
 
-    LOG_DBG("resize: %dx%d, grid: cols=%d, rows=%d",
-            c->width, c->height, c->term.cols, c->term.rows);
+    LOG_INFO("resize: %dx%d, grid: cols=%d, rows=%d",
+             c->width, c->height, c->term.cols, c->term.rows);
 
     /* Update environment variables */
     char cols_s[12], rows_s[12];
-    sprintf(cols_s, "%u", c->term.cols);
-    sprintf(rows_s, "%u", c->term.rows);
+    sprintf(cols_s, "%d", c->term.cols);
+    sprintf(rows_s, "%d", c->term.rows);
     setenv("COLUMNS", cols_s, 1);
     setenv("LINES", rows_s, 1);
 
@@ -469,6 +559,11 @@ resize(struct context *c, int width, int height)
     if (c->term.scroll_region.end == old_rows)
         c->term.scroll_region.end = c->term.rows;
 
+    term_cursor_to(
+        &c->term,
+        min(c->term.cursor.row, c->term.rows),
+        min(c->term.cursor.col, c->term.cols));
+
     term_damage_all(&c->term);
 
     if (!c->frame_is_scheduled)
@@ -721,10 +816,40 @@ keyboard_repeater(void *arg)
 }
 
 int
-main(int argc, const char *const *argv)
+main(int argc, char *const *argv)
 {
     int ret = EXIT_FAILURE;
 
+    static const struct option longopts[] =  {
+        {"font", required_argument, 0, 'f'},
+        {NULL,   no_argument,       0,   0},
+    };
+
+    const char *font_name = "Dina:pixelsize=12";
+
+    while (true) {
+        int c = getopt_long(argc, argv, ":f:h", longopts, NULL);
+        if (c == -1)
+            break;
+
+        switch (c) {
+        case 'f':
+            font_name = optarg;
+            break;
+
+        case 'h':
+            break;
+
+        case ':':
+            fprintf(stderr, "error: -%c: missing required argument\n", optopt);
+            return EXIT_FAILURE;
+
+        case '?':
+            fprintf(stderr, "error: -%c: invalid option\n", optopt);
+            return EXIT_FAILURE;
+        }
+    }
+
     setlocale(LC_ALL, "");
 
     int repeat_pipe_fds[2] = {-1, -1};
@@ -739,6 +864,7 @@ main(int argc, const char *const *argv)
             .ptmx = posix_openpt(O_RDWR | O_NOCTTY),
             .decckm = DECCKM_CSI,
             .keypad_mode = KEYPAD_NUMERICAL,  /* TODO: verify */
+            .auto_margin = true,
             .vt = {
                 .state = 1,  /* STATE_GROUND */
             },
@@ -764,7 +890,6 @@ main(int argc, const char *const *argv)
     thrd_t keyboard_repeater_id;
     thrd_create(&keyboard_repeater_id, &keyboard_repeater, &c.term);
 
-    const char *font_name = "Dina:pixelsize=12";
     c.fonts[0] = font_from_name(font_name);
     if (c.fonts[0] == NULL)
         goto out;
@@ -779,11 +904,11 @@ main(int argc, const char *const *argv)
 
         snprintf(fname, sizeof(fname), "%s:style=bold italic", font_name);
         c.fonts[3] = font_from_name(fname);
-
-        /* TODO; underline */
     }
 
     cairo_scaled_font_extents(c.fonts[0],  &c.fextents);
+    c.term.cell_width = (int)ceil(c.fextents.max_x_advance);
+    c.term.cell_height = (int)ceil(c.fextents.height);
 
     LOG_DBG("font: height: %.2f, x-advance: %.2f",
             c.fextents.height, c.fextents.max_x_advance);
@@ -864,6 +989,20 @@ main(int argc, const char *const *argv)
         break;
     }
 
+    /* Read logic requires non-blocking mode */
+    {
+        int fd_flags = fcntl(c.term.ptmx, F_GETFL);
+        if (fd_flags == -1) {
+            LOG_ERRNO("failed to set non blocking mode on PTY master");
+            goto out;
+        }
+
+        if (fcntl(c.term.ptmx, F_SETFL, fd_flags | O_NONBLOCK) == -1) {
+            LOG_ERRNO("failed to set non blocking mode on PTY master");
+            goto out;
+        }
+    }
+
     while (true) {
         struct pollfd fds[] = {
             {.fd = wl_display_get_fd(c.wl.display), .events = POLLIN},
@@ -888,16 +1027,18 @@ main(int argc, const char *const *argv)
         }
 
         if (fds[1].revents & POLLIN) {
-            uint8_t data[8192];
-            ssize_t count = read(c.term.ptmx, data, sizeof(data));
-            if (count < 0) {
-                LOG_ERRNO("failed to read from pseudo terminal");
-                break;
+            for (size_t i = 0; i < 3; i++) {
+                uint8_t data[8192];
+                ssize_t count = read(c.term.ptmx, data, sizeof(data));
+                if (count < 0) {
+                    if (errno != EAGAIN)
+                        LOG_ERRNO("failed to read from pseudo terminal");
+                    break;
+                }
+
+                vt_from_slave(&c.term, data, count);
             }
 
-            //LOG_DBG("%.*s", (int)count, data);
-
-            vt_from_slave(&c.term, data, count);
             if (!c.frame_is_scheduled)
                 grid_render(&c);
         }
diff --git a/osc.c b/osc.c
index 5f71287e..2882d546 100644
--- a/osc.c
+++ b/osc.c
@@ -1,7 +1,7 @@
 #include "osc.h"
 
 #define LOG_MODULE "osc"
-#define LOG_ENABLE_DBG 1
+#define LOG_ENABLE_DBG 0
 #include "log.h"
 
 bool
diff --git a/slave.c b/slave.c
index edb5e9c6..676d4ce2 100644
--- a/slave.c
+++ b/slave.c
@@ -9,7 +9,7 @@
 #include <fcntl.h>
 
 #define LOG_MODULE "slave"
-#define LOG_ENABLE_DBG 1
+#define LOG_ENABLE_DBG 0
 #include "log.h"
 
 void
diff --git a/terminal.c b/terminal.c
index 482452c5..4de5a1a8 100644
--- a/terminal.c
+++ b/terminal.c
@@ -4,8 +4,9 @@
 #include <assert.h>
 
 #define LOG_MODULE "terminal"
-#define LOG_ENABLE_DBG 1
+#define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "grid.h"
 
 #define min(x, y) ((x) < (y) ? (x) : (y))
 #define max(x, y) ((x) > (y) ? (x) : (y))
@@ -37,10 +38,6 @@ damage_merge_range(struct terminal *term, const struct damage *dmg)
         old->range.start = new_start;
         old->range.length = new_end - new_start;
 
-        assert(old->range.start >= 0);
-        assert(old->range.start < term->rows * term->cols);
-        assert(old->range.length >= 0);
-        assert(old->range.start + old->range.length <= term->rows * term->cols);
         return true;
     }
 
@@ -51,16 +48,18 @@ static void
 term_damage_update_or_erase(struct terminal *term, enum damage_type damage_type,
                             int start, int length)
 {
+#if 1
+    if (tll_length(term->grid->damage) > 1024) {
+        term_damage_all(term);
+        return;
+    }
+#endif
+
     struct damage dmg = {
         .type = damage_type,
-        .range = {.start = start, .length = length},
+        .range = {.start = term->grid->offset + start, .length = length},
     };
 
-    assert(dmg.range.start >= 0);
-    assert(dmg.range.start < term->rows * term->cols);
-    assert(dmg.range.length >= 0);
-    assert(dmg.range.start + dmg.range.length <= term->rows * term->cols);
-
     if (damage_merge_range(term, &dmg))
         return;
 
@@ -70,12 +69,14 @@ term_damage_update_or_erase(struct terminal *term, enum damage_type damage_type,
 void
 term_damage_update(struct terminal *term, int start, int length)
 {
+    assert(start + length <= term->rows * term->cols);
     term_damage_update_or_erase(term, DAMAGE_UPDATE, start, length);
 }
 
 void
 term_damage_erase(struct terminal *term, int start, int length)
 {
+    assert(start + length <= term->rows * term->cols);
     term_damage_update_or_erase(term, DAMAGE_ERASE, start, length);
 }
 
@@ -87,82 +88,53 @@ term_damage_all(struct terminal *term)
     term_damage_update(term, 0, term->rows * term->cols);
 }
 
+#if 0
 static void
 damage_adjust_after_scroll(struct terminal *term, enum damage_type damage_type,
                            struct scroll_region region, int lines)
 {
-    const int adjustment
-        = lines * term->cols * (damage_type == DAMAGE_SCROLL_REVERSE ? -1 : 1);
-
-    const int scroll_start = region.start * term->cols;
-    const int scroll_end = region.end * term->cols;
-
     tll_foreach(term->grid->damage, it) {
+#if 0
+        if (it->item.range.start < term->grid->offset) {
+            int end = it->item.range.start + it->item.range.length;
+            if (end >= term->grid->offset) {
+                it->item.range.start = term->grid->offset;
+                it->item.range.length = end - it->item.range.start;
+            } else {
+                tll_remove(term->grid->damage, it);
+            }
+        }
+#endif
+
         int start = it->item.range.start;
-        int length = it->item.range.length;
-        int end = start + length;
+        int end = start + it->item.range.length;
 
-        if (start < scroll_start && end > scroll_start) {
-            /* Start outside, end either inside or on the other side */
-            struct damage outside = {
-                .type = it->item.type,
-                .range = {.start = start, .length = scroll_start - start},
-            };
-
-            tll_push_back(term->grid->damage, outside);
-            start = scroll_start;
-            length = end - start;
-
-        }
-
-        if (start < scroll_end && end > scroll_end) {
-            /* End outside, start either inside or on the other side */
-            struct damage outside = {
-                .type = it->item.type,
-                .range = {.start = scroll_end, .length = length - scroll_end},
-            };
-
-            tll_push_back(term->grid->damage, outside);
-            end = scroll_end;
-            length = end - start;
-        }
-
-        if (start >= scroll_start && end <= scroll_end) {
-            /* Completely inside scroll region */
-            start -= adjustment;
-            it->item.range.start = start;
-
-            if (start < scroll_start) {
-                /* Scrolled up outside scroll region */
-                int new_length = length - (scroll_start - start);
-                assert(new_length < length);
-
-                if (new_length <= 0)
-                    tll_remove(term->grid->damage, it);
-                else {
-                    it->item.range.start = scroll_start;
-                    it->item.range.length = new_length;
-                }
-            }
-
-            if (start + length > scroll_end) {
-                /* Scrolled down outside scroll region */
-                if (start >= scroll_end)
-                    tll_remove(term->grid->damage, it);
-                else {
-                    it->item.range.start = start;
-                    it->item.range.length = scroll_end - start;
-                }
-            }
-        }
+        if (start - 
     }
 }
+#endif
 
 void
 term_damage_scroll(struct terminal *term, enum damage_type damage_type,
                    struct scroll_region region, int lines)
 {
-    damage_adjust_after_scroll(term, damage_type, region, lines);
+    //damage_adjust_after_scroll(term, damage_type, region, lines);
+    if (damage_type == DAMAGE_SCROLL) {
+        tll_foreach(term->grid->damage, it) {
+            int start = it->item.range.start;
+            int length = it->item.range.length;
+
+            if (start < term->grid->offset) {
+                int end = start + length;
+                if (end >= term->grid->offset) {
+                    it->item.range.start = term->grid->offset;
+                    it->item.range.length = end - it->item.range.start;
+                } else
+                    tll_remove(term->grid->damage, it);
+            } else
+                break;
+        }
+    }
 
     if (tll_length(term->grid->scroll_damage) > 0) {
         struct damage *dmg = &tll_back(term->grid->scroll_damage);
@@ -185,8 +157,11 @@ term_damage_scroll(struct terminal *term, enum damage_type damage_type,
 void
 term_erase(struct terminal *term, int start, int end)
 {
+    LOG_DBG("erase: %d-%d", start, end);
     assert(end >= start);
-    memset(&term->grid->cells[start], 0, (end - start) * sizeof(term->grid->cells[0]));
+    assert(end <= term->rows * term->cols);
+
+    grid_memset(term->grid, start, 0, end - start);
     term_damage_erase(term, start, end - start);
 }
 
@@ -199,36 +174,41 @@ term_cursor_linear(const struct terminal *term, int row, int col)
 void
 term_cursor_to(struct terminal *term, int row, int col)
 {
-    assert(row >= 0);
     assert(row < term->rows);
-    assert(col >= 0);
     assert(col < term->cols);
 
     int new_linear = row * term->cols + col;
-    assert(new_linear >= 0);
     assert(new_linear < term->rows * term->cols);
 
-    term_damage_update(term, term->cursor.linear, 1);
-    term_damage_update(term, new_linear, 1);
     term->print_needs_wrap = false;
 
     term->cursor.linear = new_linear;
     term->cursor.col = col;
     term->cursor.row = row;
+
+    int len = term->cols;
+    term->grid->cur_line = grid_get_range(
+        term->grid, term->cursor.linear - col, &len);
+
+    assert(len == term->cols);
 }
 
 void
 term_cursor_left(struct terminal *term, int count)
 {
     int move_amount = min(term->cursor.col, count);
-    term_cursor_to(term, term->cursor.row, term->cursor.col - move_amount);
+    term->cursor.linear -= move_amount;
+    term->cursor.col -= move_amount;
+    term->print_needs_wrap = false;
 }
 
 void
 term_cursor_right(struct terminal *term, int count)
 {
     int move_amount = min(term->cols - term->cursor.col - 1, count);
-    term_cursor_to(term, term->cursor.row, term->cursor.col + move_amount);
+    term->cursor.linear += move_amount;
+    term->cursor.col += move_amount;
+    term->print_needs_wrap = false;
 }
 
 void
@@ -248,27 +228,61 @@ term_cursor_down(struct terminal *term, int count)
 void
 term_scroll_partial(struct terminal *term, struct scroll_region region, int rows)
 {
-    if (rows >= region.end - region.start) {
-        assert(false && "untested");
-        return;
+    LOG_DBG("scroll: %d rows", rows);
+
+    if (region.start > 0) {
+        /* TODO: check if it's worth memoving the scroll area instead,
+         * under certain circumstances */
+
+        grid_memmove(term->grid, rows * term->cols, 0, region.start * term->cols);
+
+        tll_foreach(term->grid->damage, it) {
+            int start = it->item.range.start - term->grid->offset;
+            int end __attribute__((unused))  = start + it->item.range.length;
+
+            if (start < region.start * term->cols) {
+                assert(end <= region.start * term->cols);
+                it->item.range.start += rows * term->cols;
+            }
+        }
     }
 
-    int cell_dst = (region.start + 0) * term->cols;
-    int cell_src = (region.start + rows) * term->cols;
-    int cell_count = (region.end - region.start - rows) * term->cols;
+    if (region.end < term->rows) {
+        /* Copy scrolled-up bottom region to new bottom region */
+        grid_memmove(
+            term->grid,
+            (region.end + rows) * term->cols,
+            region.end * term->cols,
+            (term->rows - region.end) * term->cols);
 
-    LOG_DBG("moving %d lines from row %d to row %d", cell_count / term->cols,
-            cell_src / term->cols, cell_dst / term->cols);
+        tll_foreach(term->grid->damage, it) {
+            int start = it->item.range.start - term->grid->offset;
+            int end = start + it->item.range.length;
 
-    const size_t bytes = cell_count * sizeof(term->grid->cells[0]);
-    memmove(
-        &term->grid->cells[cell_dst], &term->grid->cells[cell_src],
-        bytes);
+            if (end > region.end * term->cols) {
+                assert(start >= region.end * term->cols);
+                it->item.range.start += rows * term->cols;
+            }
+        }
+    }
 
-    memset(&term->grid->cells[(region.end - rows) * term->cols], 0,
-           rows * term->cols * sizeof(term->grid->cells[0]));
+    /* Offset grid origin */
+    term->grid->offset += rows * term->cols;
+
+    /* Clear scrolled-in lines */
+    grid_memset(
+        term->grid,
+        max(0, region.end - rows) * term->cols,
+        0,
+        min(rows, term->rows) * term->cols);
 
     term_damage_scroll(term, DAMAGE_SCROLL, region, rows);
+
+    int len = term->cols;
+    term->grid->cur_line = grid_get_range(
+        term->grid, term->cursor.linear - term->cursor.col, &len);
+
+    assert(len == term->cols);
 }
 
 void
@@ -281,27 +295,56 @@ void
 term_scroll_reverse_partial(struct terminal *term,
                             struct scroll_region region, int rows)
 {
-    if (rows >= region.end - region.start) {
-        assert(false && "todo");
-        return;
+    if (region.end < term->rows) {
+        grid_memmove(
+            term->grid,
+            (region.end - rows) * term->cols,
+            region.end * term->cols,
+            (term->rows - region.end) * term->cols);
+
+        tll_foreach(term->grid->damage, it) {
+            int start = it->item.range.start - term->grid->offset;
+            int end = start + it->item.range.length;
+
+            if (end > region.end * term->cols) {
+                assert(start >= region.end * term->cols);
+                it->item.range.start -= rows * term->cols;
+            }
+        }
+
     }
 
-    int cell_dst = (region.start + rows) * term->cols;
-    int cell_src = (region.start + 0) * term->cols;
-    int cell_count = (region.end - region.start - rows) * term->cols;
+    if (region.start > 0) {
+        grid_memmove(
+            term->grid, -rows * term->cols, 0, region.start * term->cols);
 
-    LOG_DBG("moving %d lines from row %d to row %d", cell_count / term->cols,
-            cell_src / term->cols, cell_dst / term->cols);
+        tll_foreach(term->grid->damage, it) {
+            int start = it->item.range.start - term->grid->offset;
+            int end __attribute__((unused))  = start + it->item.range.length;
 
-    const size_t bytes = cell_count * sizeof(term->grid->cells[0]);
-    memmove(
-        &term->grid->cells[cell_dst], &term->grid->cells[cell_src],
-        bytes);
+            if (start < region.start * term->cols) {
+                if (end > region.start * term->cols) {
+                    LOG_ERR("region.start = %d, rows = %d, damage.start = %d, damage.end = %d (%s)",
+                            region.start, rows, start, end, it->item.type == DAMAGE_UPDATE ? "UPDATE" : "ERASE");
+                    abort();
+                }
+                assert(end <= region.start * term->cols);
+                it->item.range.start -= rows * term->cols;
+            }
+        }
+    }
 
-    memset(&term->grid->cells[cell_src], 0,
-           rows * term->cols * sizeof(term->grid->cells[0]));
+    term->grid->offset -= rows * term->cols;
+
+    grid_memset(term->grid, region.start * term->cols, 0, rows * term->cols);
 
     term_damage_scroll(term, DAMAGE_SCROLL_REVERSE, region, rows);
+
+    int len = term->cols;
+    term->grid->cur_line = grid_get_range(
+        term->grid, term->cursor.linear - term->cursor.col, &len);
+
+    assert(len == term->cols);
 }
 
 void
diff --git a/terminal.h b/terminal.h
index cceaa6b6..f48158e5 100644
--- a/terminal.h
+++ b/terminal.h
@@ -62,10 +62,11 @@ struct damage {
 };
 
 struct grid {
-    size_t size;
-    size_t offset;
+    int size;
+    int offset;
 
     struct cell *cells;
+    struct cell *cur_line;
 
     tll(struct damage) damage;
     tll(struct damage) scroll_damage;
@@ -73,7 +74,7 @@ struct grid {
 
 struct vt_subparams {
     unsigned value[16];
-    size_t idx;
+    int idx;
 };
 
 struct vt_param {
@@ -85,20 +86,20 @@ struct vt {
     int state;  /* enum state */
     struct {
         struct vt_param v[16];
-        size_t idx;
+        int idx;
     } params;
     struct {
         uint8_t data[2];
-        size_t idx;
+        int idx;
     } intermediates;
     struct {
         uint8_t data[1024];
-        size_t idx;
+        int idx;
     } osc;
     struct {
         uint8_t data[4];
-        size_t idx;
-        size_t left;
+        int idx;
+        int left;
     } utf8;
     struct attributes attrs;
     bool dim;
@@ -132,6 +133,9 @@ struct terminal {
 
     enum decckm decckm;
     enum keypad_mode keypad_mode;
+    bool hide_cursor;
+    bool auto_margin;
+    bool insert_mode;
     bool bracketed_paste;
 
     struct vt vt;
diff --git a/vt.c b/vt.c
index c7e75a94..8f1db921 100644
--- a/vt.c
+++ b/vt.c
@@ -5,7 +5,7 @@
 #include <assert.h>
 
 #define LOG_MODULE "vt"
-#define LOG_ENABLE_DBG 1
+#define LOG_ENABLE_DBG 0
 #include "log.h"
 #include "csi.h"
 #include "osc.h"
@@ -555,7 +555,7 @@ static const enum action exit_actions[] = {
 static bool
 esc_dispatch(struct terminal *term, uint8_t final)
 {
-#if defined(_DEBUG) && defined(LOG_ENABLE_DBG) && LOG_ENABLED_DBG
+#if defined(_DEBUG) && defined(LOG_ENABLE_DBG) && LOG_ENABLE_DBG
     char log[1024];
     int c = snprintf(log, sizeof(log), "ESC: ");
 
@@ -568,6 +568,7 @@ esc_dispatch(struct terminal *term, uint8_t final)
 
     switch (final) {
     case 'B': {
+        /* Configure G0-G3 to use ASCII */
         char param = term->vt.params.idx > 0 ? term->vt.params.v[0].value : '(';
 
         switch (param) {
@@ -578,11 +579,30 @@ esc_dispatch(struct terminal *term, uint8_t final)
         case ')':
         case '*':
         case '+':
-            LOG_ERR("unimplemented: character charset: %c", param);
+            LOG_WARN("unimplemented: charset %c uses ASCII", param);
             return false;
 
         default:
-            LOG_ERR("ESC <id> B: invalid charset identifier: %c", param);
+            LOG_ERR("<ESC>%cB: invalid charset identifier", param);
+            return false;
+        }
+        break;
+    }
+
+    case '0': {
+        /* Configure G0-G3 to use special chars + line drawing */
+        char param = term->vt.params.idx > 0 ? term->vt.params.v[0].value : '(';
+
+        switch (param) {
+        case '(':
+        case ')':
+        case '*':
+        case '+':
+            LOG_WARN("unimplemented: charset %c uses special characters and line drawings", param);
+            break;
+
+        default:
+            LOG_ERR("<ESC>%c0: invalid charset identifier", param);
             return false;
         }
         break;
@@ -664,13 +684,13 @@ action(struct terminal *term, enum action action, uint8_t c)
 
     case ACTION_CLEAR:
         memset(&term->vt.params, 0, sizeof(term->vt.params));
-        memset(&term->vt.intermediates, 0, sizeof(term->vt.intermediates));
-        memset(&term->vt.osc, 0, sizeof(term->vt.osc));
-        memset(&term->vt.utf8, 0, sizeof(term->vt.utf8));
+        term->vt.intermediates.idx = 0;
+        term->vt.osc.idx = 0;
+        term->vt.utf8.idx = 0;
         break;
 
     case ACTION_PRINT: {
-        if (term->print_needs_wrap) {
+        if (term->auto_margin && term->print_needs_wrap) {
             if (term->cursor.row == term->scroll_region.end - 1) {
                 term_scroll(term, 1);
                 term_cursor_to(term, term->cursor.row, 0);
@@ -678,14 +698,22 @@ action(struct terminal *term, enum action action, uint8_t c)
                 term_cursor_to(term, term->cursor.row + 1, 0);
         }
 
-        struct cell *cell = &term->grid->cells[term->cursor.linear];
+        struct cell *cell = &term->grid->cur_line[term->cursor.col];
         term_damage_update(term, term->cursor.linear, 1);
 
+        if (term->insert_mode) {
+            assert(false && "untested");
+            grid_memmove(
+                term->grid, term->cursor.linear + 1, term->cursor.linear,
+                term->cols - term->cursor.col - 1);
+            term_damage_update(
+                term, term->cursor.linear + 1, term->cols - term->cursor.col - 1);
+        }
+
         if (term->vt.utf8.idx > 0) {
             //LOG_DBG("print: UTF8: %.*s", (int)term->vt.utf8.idx, term->vt.utf8.data);
             memcpy(cell->c, term->vt.utf8.data, term->vt.utf8.idx);
             cell->c[term->vt.utf8.idx] = '\0';
-            memset(&term->vt.utf8, 0, sizeof(term->vt.utf8));
         } else {
             //LOG_DBG("print: ASCII: %c", c);
             cell->c[0] = c;