From bcf763d41776705ad62972e766d73fd9533bbb9e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Thu, 11 Jul 2019 09:51:51 +0200
Subject: [PATCH] selection: add a selection API

---
 input.c     | 45 +++++++++++++---------------------
 meson.build |  1 +
 selection.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 selection.h |  8 ++++++
 terminal.c  | 19 +++++++++++++--
 terminal.h  |  4 +++
 6 files changed, 117 insertions(+), 30 deletions(-)
 create mode 100644 selection.c
 create mode 100644 selection.h

diff --git a/input.c b/input.c
index a6369a51..e075bf4b 100644
--- a/input.c
+++ b/input.c
@@ -20,6 +20,7 @@
 #include "render.h"
 #include "keymap.h"
 #include "commands.h"
+#include "selection.h"
 
 static void
 keyboard_keymap(void *data, struct wl_keyboard *wl_keyboard,
@@ -178,10 +179,10 @@ keyboard_key(void *data, struct wl_keyboard *wl_keyboard, uint32_t serial,
 
             if (term->grid->view != term->grid->offset) {
                 term->grid->view = term->grid->offset;
-                /* TODO: damage view */
                 term_damage_all(term);
             }
 
+            selection_cancel(term);
             break;
         }
     }
@@ -207,10 +208,10 @@ keyboard_key(void *data, struct wl_keyboard *wl_keyboard, uint32_t serial,
 
             if (term->grid->view != term->grid->offset) {
                 term->grid->view = term->grid->offset;
-                /* TODO: damage view */
                 term_damage_all(term);
             }
 
+            selection_cancel(term);
         }
     }
 
@@ -306,19 +307,20 @@ wl_pointer_motion(void *data, struct wl_pointer *wl_pointer,
     int col = x / term->cell_width;
     int row = y / term->cell_height;
 
+    bool update_selection = term->mouse.button == BTN_LEFT;
+    bool update_selection_early = term->selection.end.row == -1;
+
+    if (update_selection && update_selection_early)
+        selection_update(term, col, row);
+
     if (col == term->mouse.col && row == term->mouse.row)
         return;
 
     term->mouse.col = col;
     term->mouse.row = row;
 
-    if (term->mouse.button == BTN_LEFT) {
-        /* Update selection */
-        term->selection.end = (struct coord){col, term->grid->view + row};
-        term_damage_view(term);
-        if (term->frame_callback == NULL)
-            grid_render(term);
-    }
+    if (update_selection && !update_selection_early)
+        selection_update(term, col, row);
 
     term_mouse_motion(
         term, term->mouse.button, term->mouse.row, term->mouse.col,
@@ -335,18 +337,10 @@ wl_pointer_button(void *data, struct wl_pointer *wl_pointer,
 
     switch (state) {
     case WL_POINTER_BUTTON_STATE_PRESSED:
-        if (button == BTN_LEFT) {
-            /* Start selection */
-            term->selection.start = (struct coord){
-                term->mouse.col, term->grid->view + term->mouse.row};
-            term->selection.end = (struct coord){-1, -1};
-        } else {
-            term->selection.start = (struct coord){-1, -1};
-            term->selection.end = (struct coord){-1, -1};
-            term_damage_view(term);
-            if (term->frame_callback == NULL)
-                grid_render(term);
-        }
+        if (button == BTN_LEFT)
+            selection_start(term, term->mouse.col, term->mouse.row);
+        else
+            selection_cancel(term);
 
         term->mouse.button = button; /* For motion events */
         term_mouse_down(term, button, term->mouse.row, term->mouse.col,
@@ -354,13 +348,8 @@ wl_pointer_button(void *data, struct wl_pointer *wl_pointer,
         break;
 
     case WL_POINTER_BUTTON_STATE_RELEASED:
-        if (button == BTN_LEFT && term->selection.end.col == -1) {
-            /* No selection made - cancel  */
-            term->selection.start = (struct coord){-1, -1};
-            term_damage_view(term);
-            if (term->frame_callback == NULL)
-                grid_render(term);
-        }
+        if (button == BTN_LEFT && term->selection.end.col == -1)
+            selection_cancel(term);
 
         term->mouse.button = 0; /* For motion events */
         term_mouse_up(term, button, term->mouse.row, term->mouse.col,
diff --git a/meson.build b/meson.build
index 7cb057bf..51ee526f 100644
--- a/meson.build
+++ b/meson.build
@@ -67,6 +67,7 @@ executable(
   'main.c',
   'osc.c', 'osc.h',
   'render.c', 'render.h',
+  'selection.c', 'selection.h',
   'shm.c', 'shm.h',
   'slave.c', 'slave.h',
   'terminal.c', 'terminal.h',
diff --git a/selection.c b/selection.c
new file mode 100644
index 00000000..b0b688b9
--- /dev/null
+++ b/selection.c
@@ -0,0 +1,70 @@
+#include "selection.h"
+
+#define LOG_MODULE "selection"
+#define LOG_ENABLE_DBG 1
+#include "log.h"
+#include "render.h"
+
+#define min(x, y) ((x) < (y) ? (x) : (y))
+#define max(x, y) ((x) > (y) ? (x) : (y))
+
+void
+selection_start(struct terminal *term, int col, int row)
+{
+    selection_cancel(term);
+
+    LOG_DBG("selection started at %d,%d", row, col);
+    term->selection.start = (struct coord){col, row};
+    term->selection.end = (struct coord){-1, -1};
+}
+
+void
+selection_update(struct terminal *term, int col, int row)
+{
+    LOG_DBG("selection updated: start = %d,%d, end = %d,%d -> %d, %d",
+            term->selection.start.row, term->selection.start.col,
+            term->selection.end.row, term->selection.end.col,
+            row, col);
+
+    term->selection.end = (struct coord){col, term->grid->view + row};
+
+    assert(term->selection.start.row != -1 && term->selection.end.row != -1);
+    term_damage_rows_in_view(
+        term,
+        min(term->selection.start.row, term->selection.end.row) - term->grid->view,
+        max(term->selection.start.row, term->selection.end.row) - term->grid->view);
+
+    if (term->frame_callback == NULL)
+        grid_render(term);
+}
+
+void
+selection_finalizie(struct terminal *term)
+{
+    assert(term->selection.start.row != -1);
+    assert(term->selection.end.row != -1);
+}
+
+void
+selection_cancel(struct terminal *term)
+{
+    LOG_DBG("selection cancelled: start = %d,%d end = %d,%d",
+            term->selection.start.row, term->selection.start.col,
+            term->selection.end.row, term->selection.end.col);
+
+    int start_row = term->selection.start.row;
+    int end_row = term->selection.end.row;
+
+    term->selection.start = (struct coord){-1, -1};
+    term->selection.end = (struct coord){-1, -1};
+
+    if (start_row != -1 && end_row != -1) {
+        term_damage_rows_in_view(
+            term,
+            min(start_row, end_row) - term->grid->view,
+            max(start_row, end_row) - term->grid->view);
+
+        if (term->frame_callback == NULL)
+            grid_render(term);
+    }
+}
diff --git a/selection.h b/selection.h
new file mode 100644
index 00000000..96b8b489
--- /dev/null
+++ b/selection.h
@@ -0,0 +1,8 @@
+#pragma once
+
+#include "terminal.h"
+
+void selection_start(struct terminal *term, int col, int row);
+void selection_update(struct terminal *term, int col, int row);
+void selection_finalizie(struct terminal *term);
+void selection_cancel(struct terminal *term);
diff --git a/terminal.c b/terminal.c
index 5b4b0f50..d6d75641 100644
--- a/terminal.c
+++ b/terminal.c
@@ -14,11 +14,26 @@
 #define min(x, y) ((x) < (y) ? (x) : (y))
 #define max(x, y) ((x) > (y) ? (x) : (y))
 
+void
+term_damage_rows(struct terminal *term, int start, int end)
+{
+    assert(start <= end);
+    for (int r = start; r <= end; r++)
+        grid_row(term->grid, r)->dirty = true;
+}
+
+void
+term_damage_rows_in_view(struct terminal *term, int start, int end)
+{
+    assert(start <= end);
+    for (int r = start; r <= end; r++)
+        grid_row_in_view(term->grid, r)->dirty = true;
+}
+
 void
 term_damage_all(struct terminal *term)
 {
-    for (int i = 0; i < term->rows; i++)
-        grid_row(term->grid, i)->dirty = true;
+    term_damage_rows(term, 0, term->rows);
 }
 
 void
diff --git a/terminal.h b/terminal.h
index 1e56567f..8b080ad9 100644
--- a/terminal.h
+++ b/terminal.h
@@ -244,8 +244,12 @@ struct terminal {
     struct wl_callback *frame_callback;
 };
 
+void term_damage_rows(struct terminal *term, int start, int end);
+void term_damage_rows_in_view(struct terminal *term, int start, int end);
+
 void term_damage_all(struct terminal *term);
 void term_damage_view(struct terminal *term);
+
 void term_damage_scroll(
     struct terminal *term, enum damage_type damage_type,
     struct scroll_region region, int lines);