Scrolling the main cursor properly

src/text_editor/buffer.cpp

@@ -154,6 +154,16 @@ String GetString(const Buffer &buffer, Range range = {0, INT64_MAX}) {
     return result;
 }
 
+bool AreEqual(Range a, Range b) {
+    bool result = a.min == b.min && a.max == b.max;
+    return result;
+}
+
+bool AreEqual(Cursor a, Cursor b) {
+    bool result = AreEqual(a.range, b.range) && a.ifront == b.ifront;
+    return result;
+}
+
 void MergeSort(int64_t Count, Edit *First, Edit *Temp) {
     // SortKey = range.min
     if (Count == 1) {
@@ -230,10 +240,10 @@ void ApplyEdits(Buffer *buffer, Array<Edit> edits) {
         ForItem(it2, edits) {
             if (&it1 == &it2) continue;
 
-            bool a2_inside = it2.range.min >= it1.range.min && it2.range.min <= it1.range.max;
+            bool a2_inside = it2.range.min >= it1.range.min && it2.range.min < it1.range.max;
             Assert(!a2_inside);
 
-            bool b2_inside = it2.range.max >= it1.range.min && it2.range.max <= it1.range.max;
+            bool b2_inside = it2.range.max > it1.range.min && it2.range.max <= it1.range.max;
             Assert(!b2_inside);
         }
     }

src/text_editor/main.cpp

@@ -21,6 +21,7 @@ struct Window {
     float    right_scroll_bar_pixel_size;
     float    bottom_scroll_bar_pixel_size;
 
+    Cursor        main_cursor_begin_frame;
     Array<Cursor> cursors;
     Buffer        buffer;
 };
@@ -187,15 +188,15 @@ int   main() {
         }
 
         window.cursors.add({});
-        for (int i = 1; i < 2; i += 1) {
-            Line line = GetLine(window.buffer, i);
-            window.cursors.add({line.range.min, line.range.min});
-        }
         windows.add(window);
     }
 
     Vec2 camera_offset_world_to_render_units = {};
     while (!WindowShouldClose()) {
+        For(windows) {
+            Assert(it.cursors.len);
+            it.main_cursor_begin_frame = it.cursors[0];
+        }
         {
             Window *focused_window = &windows[0];
 
@@ -210,6 +211,10 @@ int   main() {
             focused_window->scroll.y -= mouse_wheel;
             focused_window->scroll.y = ClampBottom(focused_window->scroll.y, 0.f);
 
+            if (IsKeyDown(KEY_LEFT_CONTROL) && IsKeyPressed(KEY_A)) {
+                focused_window->cursors.clear();
+                focused_window->cursors.add(MakeCursor(0, focused_window->buffer.len));
+            }
             if (IsKeyPressed(KEY_LEFT) || IsKeyPressedRepeat(KEY_LEFT)) {
                 For(focused_window->cursors) {
                     if (IsKeyDown(KEY_LEFT_CONTROL)) {
@@ -327,6 +332,7 @@ int   main() {
                     }
                 }
             }
+            BeforeEdit(focused_window);
 
             if (IsKeyDown(KEY_LEFT_CONTROL) && IsKeyPressed(KEY_C)) {
                 Array<String> strings = {FrameArena};
@@ -348,20 +354,22 @@ int   main() {
                 ApplyEdits(&focused_window->buffer, edits);
                 AfterEdit(focused_window, edits);
             }
+
             if (IsKeyDown(KEY_LEFT_CONTROL) && (IsKeyPressed(KEY_X) || IsKeyPressedRepeat(KEY_X))) {
+                // First, if there is no selection - select the entire line
+                For(focused_window->cursors) {
+                    if (GetRangeSize(it.range) == 0) {
+                        Line line = FindLine(focused_window->buffer, it.range.min);
+                        it.range  = {line.range.min, line.range.max + 1};
+                    }
+                }
+
                 BeforeEdit(focused_window);
                 Array<Edit>   edits   = {FrameArena};
                 Array<String> strings = {FrameArena};
                 For(focused_window->cursors) {
-                    Range range = {};
+                    AddEdit(&edits, it.range, "");
-                    if (GetRangeSize(it.range)) {
+                    String string = GetString(focused_window->buffer, it.range);
-                        range = it.range;
-                    } else {
-                        Line line = FindLine(focused_window->buffer, it.range.min);
-                        range     = {line.range.min, line.range.max + 1};
-                    }
-                    AddEdit(&edits, range, "");
-                    String string = GetString(focused_window->buffer, range);
                     strings.add(string);
                 }
                 String to_save = Merge(FrameArena, strings, "\n");
@@ -370,6 +378,24 @@ int   main() {
                 AfterEdit(focused_window, edits);
             }
 
+            if (IsKeyPressed(KEY_ENTER)) {
+                if (IsKeyDown(KEY_LEFT_CONTROL)) {
+                } else {
+                }
+            }
+
+            if (IsKeyPressed(KEY_HOME) || IsKeyPressedRepeat(KEY_HOME)) {
+                if (IsKeyDown(KEY_LEFT_SHIFT)) {
+                } else {
+                }
+            }
+
+            if (IsKeyPressed(KEY_END) || IsKeyPressedRepeat(KEY_END)) {
+                if (IsKeyDown(KEY_LEFT_SHIFT)) {
+                } else {
+                }
+            }
+
             // @todo: scrolling
             if (IsKeyPressed(KEY_DELETE) || IsKeyPressedRepeat(KEY_DELETE)) {
                 if (IsKeyDown(KEY_LEFT_SHIFT)) {
@@ -377,16 +403,17 @@ int   main() {
             }
             if (IsKeyPressed(KEY_BACKSPACE) || IsKeyPressedRepeat(KEY_BACKSPACE)) {
                 if (IsKeyDown(KEY_LEFT_SHIFT)) {
+                } else {
+                    BeforeEdit(focused_window);
+                    Array<Edit> edits  = {FrameArena};
+                    String      string = {};
+                    For(focused_window->cursors) {
+                        int64_t pos = MoveLeft(focused_window->buffer, it.range.min);
+                        AddEdit(&edits, {pos, it.range.min}, string);
+                    }
+                    ApplyEdits(&focused_window->buffer, edits);
+                    AfterEdit(focused_window, edits);
                 }
-                BeforeEdit(focused_window);
-                Array<Edit> edits  = {FrameArena};
-                String      string = {};
-                For(focused_window->cursors) {
-                    int64_t pos = MoveLeft(focused_window->buffer, it.range.min);
-                    AddEdit(&edits, {pos, it.range.min}, string);
-                }
-                ApplyEdits(&focused_window->buffer, edits);
-                AfterEdit(focused_window, edits);
             }
 
             // Handle user input
@@ -463,7 +490,7 @@ int   main() {
             Array<CellRow> rows = {FrameArena};
             {
                 // Figure out which lines to draw
-                Vec2    s           = GetSize(window_rect_in_render_units);
+                Vec2    s           = GetSize(window_text_rect_in_render_units);
                 float   line_offset = font_size;
                 float   _line_min_y = (window.scroll.y) / line_offset;
                 float   _line_max_y = (s.y + window.scroll.y) / line_offset;
@@ -528,6 +555,29 @@ int   main() {
                     if (row.cells.len) rows.add(row);
                 }
             }
+            Assert(rows.len);
+
+            // @todo: x axis
+            // @tood: moving using mouse
+            // Update the scroll based on first cursor
+            if (!AreEqual(window.main_cursor_begin_frame, window.cursors[0])) {
+                Vec2  rect_in_render_units          = GetSize(window_text_rect_in_render_units_clamped_to_screen);
+                float visible_cells_in_render_units = font_size * (float)rows.len;
+                float cut_off_in_render_units       = visible_cells_in_render_units - rect_in_render_units.y;
+
+                Cursor  cursor   = window.cursors[0];
+                int64_t front    = GetFront(cursor);
+                Line    line     = FindLine(window.buffer, front);
+                int64_t min_line = rows[0].line;
+                int64_t max_line = rows[rows.len - 1].line;
+
+                if (line.number < min_line) {
+                    window.scroll.y = line.number * font_size;
+                } else if (line.number >= max_line) {
+                    int64_t diff    = line.number - max_line;
+                    window.scroll.y = (min_line + diff) * font_size + cut_off_in_render_units;
+                }
+            }
 
             // Draw debug markers
             if (0) {