Add pad-extend option

config.c

@@ -977,6 +977,9 @@ parse_section_main(struct context *ctx)
         return true;
     }
 
+    else if (streq(key, "pad-extend"))
+        return value_to_bool(ctx, &conf->pad_extend);
+
     else if (streq(key, "resize-delay-ms"))
         return value_to_uint16(ctx, 10, &conf->resize_delay_ms);
 
@@ -3458,6 +3461,7 @@ config_load(struct config *conf, const char *conf_path,
         },
         .pad_x = 0,
         .pad_y = 0,
+        .pad_extend = false,
         .center_when = CENTER_MAXIMIZED_AND_FULLSCREEN,
         .resize_by_cells = true,
         .resize_keep_grid = true,

config.h

@@ -234,6 +234,7 @@ struct config {
 
     unsigned pad_x;
     unsigned pad_y;
+    bool pad_extend;
     enum center_when center_when;
 
     bool resize_by_cells;

render.c

@@ -1246,44 +1246,133 @@ render_urgency(struct terminal *term, struct buffer *buf)
         });
 }
 
+static uint32_t
+cell_bg_color(const struct terminal *term, const struct cell *cell)
+{
+    switch (cell->attrs.bg_src) {
+    case COLOR_RGB:
+        return cell->attrs.bg;
+    case COLOR_BASE16:
+    case COLOR_BASE256:
+        return term->colors.table[cell->attrs.bg];
+    case COLOR_DEFAULT:
+    default:
+        return term->reverse ? term->colors.fg : term->colors.bg;
+    }
+}
+
 static void
 render_margin(struct terminal *term, struct buffer *buf,
               int start_line, int end_line, bool apply_damage)
 {
-    /* Fill area outside the cell grid with the default background color */
     const int rmargin = term->width - term->margins.right;
     const int bmargin = term->height - term->margins.bottom;
     const int line_count = end_line - start_line;
 
     const bool gamma_correct = wayl_do_linear_blending(term->wl, term->conf);
-    const uint32_t _bg = !term->reverse ? term->colors.bg : term->colors.fg;
+    const uint32_t default_bg = !term->reverse ? term->colors.bg : term->colors.fg;
     uint16_t alpha = term->colors.alpha;
 
-    if (term->window->is_fullscreen) {
-        /* Disable alpha in fullscreen - see render_cell() for details */
+    if (term->window->is_fullscreen)
         alpha = 0xffff;
-    }
 
-    pixman_color_t bg = color_hex_to_pixman_with_alpha(_bg, alpha, gamma_correct);
+    pixman_color_t bg = color_hex_to_pixman_with_alpha(default_bg, alpha, gamma_correct);
 
-    pixman_image_fill_rectangles(
-        PIXMAN_OP_SRC, buf->pix[0], &bg, 4,
+    /* Default behavior: fill with background color */
+    pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &bg, 4,
         (pixman_rectangle16_t[]){
-            /* Top */
             {0, 0, term->width, term->margins.top},
-
-            /* Bottom */
             {0, bmargin, term->width, term->margins.bottom},
-
-            /* Left */
             {0, term->margins.top + start_line * term->cell_height,
              term->margins.left, line_count * term->cell_height},
-
-            /* Right */
             {rmargin, term->margins.top + start_line * term->cell_height,
              term->margins.right, line_count * term->cell_height},
-    });
+        });
 
+    /* Extended mode: overlay edge cell colors */
+    if (!term->conf->pad_extend)
+        goto done;
+
+    /* Left/right margins: extend each row's edge cell colors */
+    for (int r = 0; r < term->rows; r++) {
+        struct row *row = grid_row_in_view(term->grid, r);
+        if (row == NULL || row->cells == NULL)
+            continue;
+
+        int y = term->margins.top + r * term->cell_height;
+
+        uint32_t left_bg = cell_bg_color(term, &row->cells[0]);
+        if (left_bg != default_bg) {
+            pixman_color_t c = color_hex_to_pixman_with_alpha(left_bg, alpha, gamma_correct);
+            pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &c, 1,
+                &(pixman_rectangle16_t){0, y, term->margins.left, term->cell_height});
+        }
+
+        uint32_t right_bg = cell_bg_color(term, &row->cells[term->cols - 1]);
+        if (right_bg != default_bg) {
+            pixman_color_t c = color_hex_to_pixman_with_alpha(right_bg, alpha, gamma_correct);
+            pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &c, 1,
+                &(pixman_rectangle16_t){rmargin, y, term->margins.right, term->cell_height});
+        }
+    }
+
+    /* Top/bottom margins: extend each column's edge cell colors */
+    struct row *top_row = grid_row_in_view(term->grid, 0);
+    struct row *bot_row = grid_row_in_view(term->grid, term->rows - 1);
+
+    for (int c = 0; c < term->cols; c++) {
+        int x = term->margins.left + c * term->cell_width;
+
+        if (top_row != NULL && top_row->cells != NULL) {
+            uint32_t top_bg = cell_bg_color(term, &top_row->cells[c]);
+            if (top_bg != default_bg) {
+                pixman_color_t col = color_hex_to_pixman_with_alpha(top_bg, alpha, gamma_correct);
+                pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &col, 1,
+                    &(pixman_rectangle16_t){x, 0, term->cell_width, term->margins.top});
+            }
+        }
+
+        if (bot_row != NULL && bot_row->cells != NULL) {
+            uint32_t bot_bg = cell_bg_color(term, &bot_row->cells[c]);
+            if (bot_bg != default_bg) {
+                pixman_color_t col = color_hex_to_pixman_with_alpha(bot_bg, alpha, gamma_correct);
+                pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &col, 1,
+                    &(pixman_rectangle16_t){x, bmargin, term->cell_width, term->margins.bottom});
+            }
+        }
+    }
+
+    /* Fill corners with horizontal edge colors (priority) */
+    if (top_row != NULL && top_row->cells != NULL) {
+        uint32_t tl = cell_bg_color(term, &top_row->cells[0]);
+        uint32_t tr = cell_bg_color(term, &top_row->cells[term->cols - 1]);
+        if (tl != default_bg) {
+            pixman_color_t c = color_hex_to_pixman_with_alpha(tl, alpha, gamma_correct);
+            pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &c, 1,
+                &(pixman_rectangle16_t){0, 0, term->margins.left, term->margins.top});
+        }
+        if (tr != default_bg) {
+            pixman_color_t c = color_hex_to_pixman_with_alpha(tr, alpha, gamma_correct);
+            pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &c, 1,
+                &(pixman_rectangle16_t){rmargin, 0, term->margins.right, term->margins.top});
+        }
+    }
+    if (bot_row != NULL && bot_row->cells != NULL) {
+        uint32_t bl = cell_bg_color(term, &bot_row->cells[0]);
+        uint32_t br = cell_bg_color(term, &bot_row->cells[term->cols - 1]);
+        if (bl != default_bg) {
+            pixman_color_t c = color_hex_to_pixman_with_alpha(bl, alpha, gamma_correct);
+            pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &c, 1,
+                &(pixman_rectangle16_t){0, bmargin, term->margins.left, term->margins.bottom});
+        }
+        if (br != default_bg) {
+            pixman_color_t c = color_hex_to_pixman_with_alpha(br, alpha, gamma_correct);
+            pixman_image_fill_rectangles(PIXMAN_OP_SRC, buf->pix[0], &c, 1,
+                &(pixman_rectangle16_t){rmargin, bmargin, term->margins.right, term->margins.bottom});
+        }
+    }
+
+done:
     if (term->render.urgency)
         render_urgency(term, buf);
 
@@ -3618,6 +3707,10 @@ grid_render(struct terminal *term)
 
     pixman_region32_fini(&damage);
 
+    /* Re-render margins to extend edge cell colors if enabled */
+    if (term->conf->pad_extend)
+        render_margin(term, buf, 0, term->rows, true);
+
     render_overlay(term);
     render_ime_preedit(term, buf);
     render_scrollback_position(term);