Refactor y cursor, add small utility for debugging, fix bug in buffer

src/text_editor/buffer.cpp

@@ -249,8 +249,11 @@ void ApplyEdits(Buffer *buffer, Array<Edit> edits) {
 #endif
 
     // We need to sort from lowest to higest based on range.min
-    Array<Edit> edits_copy = edits.copy(scratch);
+    {
-    MergeSort(edits.len, edits_copy.data, edits.data);
+        Array<Edit> edits_copy = edits.copy(scratch);
+        MergeSort(edits.len, edits_copy.data, edits.data);
+        edits = edits_copy;
+    }
 
     // Try resizing the buffers
     int64_t len_offset              = size_to_insert - size_to_delete;

src/text_editor/main.cpp

@@ -107,6 +107,11 @@ int64_t MoveUp(Buffer &buffer, int64_t pos) {
     return new_pos;
 }
 
+bool AreEqual(float a, float b, float epsilon = 0.001f) {
+    bool result = (a - epsilon < b && a + epsilon > b);
+    return result;
+}
+
 void BeforeEdit(Window *window) {
     // Merge cursors that overlap, this needs to be handled before any edits to
     // make sure overlapping edits won't happen.
@@ -157,8 +162,34 @@ void AfterEdit(Window *window, Array<Edit> edits) {
     window->layout = CalculateLayout(&window->layout_arena, window->buffer, window->font, window->font_size, window->font_spacing);
 }
 
+Arena PermArena;
 Arena FrameArena;
-int   main() {
+struct DebugLine {
+    bool   persist;
+    String string;
+};
+Array<DebugLine> DebugLines = {};
+
+void Dbg(const char *str, ...) {
+    STRING_FORMAT(FrameArena, str, result);
+    DebugLines.add({false, result});
+}
+void DbgPersist(const char *str, ...) {
+    STRING_FORMAT(PermArena, str, result);
+    DebugLines.add({true, result});
+}
+
+void Dbg_Draw() {
+    int y = 0;
+    IterRemove(DebugLines) {
+        IterRemovePrepare(DebugLines);
+        if (it.persist == false) remove_item = true;
+        DrawText(it.string.data, 0, y, 20, BLACK);
+        y += 20;
+    }
+}
+
+int main() {
     InitScratch();
     RunBufferTests();
 
@@ -166,6 +197,7 @@ int   main() {
     SetTargetFPS(60);
 
     InitArena(&FrameArena);
+    InitArena(&PermArena);
     float font_size    = 64;
     float font_spacing = 1;
     Font  font         = LoadFontEx("C:/Windows/Fonts/times.ttf", (int)font_size, NULL, 250);
@@ -458,6 +490,7 @@ int   main() {
             Array<LayoutColumn> visible_columns = CalculateVisibleColumns(&FrameArena, window);
             // Mouse selection
             // @todo: multicursor
+            // @todo: selecting while not hovering over glyph shapes
             {
                 SetMouseCursor(MOUSE_CURSOR_DEFAULT);
                 Vec2 mouse        = GetMousePosition();
@@ -485,7 +518,7 @@ int   main() {
                             window.mouse_selecting = false;
                         }
                         Cursor *cursor = window.cursors.last();
-                        cursor[0]      = ChangeBack(*cursor, rowcol.b->pos);
+                        cursor[0]      = ChangeFront(*cursor, rowcol.b->pos);
                     }
                 }
             }
@@ -493,13 +526,38 @@ int   main() {
             // Update the scroll based on first cursor
             // @todo: needs a rewrite, make sure we also handle scrolling for mouse
             if (!AreEqual(window.main_cursor_begin_frame, window.cursors[0])) {
+#if 1
+                Range   visible_line_range = CalculateVisibleLineRange(window);
+                int64_t visible_lines      = GetRangeSize(visible_line_range);
+                float   visible_size_y     = font_size * (float)visible_lines;
+
+                Vec2  rect_size = GetSize(window.rect);
+                float cut_off_y = visible_size_y - rect_size.y;
+
+                int64_t front = GetFront(window.cursors[0]);
+                Line    line  = FindLine(window.buffer, front);
+                // Tuple<LayoutRow, LayoutColumn> rowcol = GetRowCol(window, front);
+
+                // DbgPersist("line num = %d visible_line_range.max = %d", (int)line.number, (int)visible_line_range.max);
+                // Bottom
+                if (line.number > visible_line_range.max - 2) {
+                    int64_t set_view_at_line = line.number - (visible_lines - 1);
+                    window.scroll.y          = (set_view_at_line * font_size) + cut_off_y;
+                }
+
+                if (line.number < visible_line_range.min + 1) {
+                    int64_t set_view_at_line = line.number;
+                    window.scroll.y          = (set_view_at_line * font_size);
+                }
+
+#else
                 Range visible_line_range            = CalculateVisibleLineRange(window);
                 Vec2  rect_size                     = GetSize(window.rect);
                 float visible_cells_in_render_units = font_size * (float)GetRangeSize(visible_line_range);
                 float cut_off_in_render_units       = visible_cells_in_render_units - rect_size.y;
 
                 Cursor  cursor = window.cursors[0];
-                int64_t front  = GetBack(cursor);
+                int64_t front  = GetFront(cursor);
                 Line    line   = FindLine(window.buffer, front);
 
                 // Scroll Y
@@ -528,14 +586,14 @@ int   main() {
                     float diff = x_cursor_position_in_window_buffer_world_units - window_buffer_world_left_edge;
                     window.scroll.x += diff;
                 }
+#endif
             }
 
-            Range visible_line_range = CalculateVisibleLineRange(window);
-
             // Draw the glyphs
             Vec2 window_rect_size = GetSize(window.rect);
             BeginScissorMode((int)window.rect.min.x, (int)window.rect.min.y, (int)window_rect_size.x, (int)window_rect_size.y);
 
+            Range visible_line_range = CalculateVisibleLineRange(window);
             for (int64_t line = visible_line_range.min; line < visible_line_range.max; line += 1) {
                 if (line < 0 || line >= window.layout.rows.len) continue;
                 LayoutRow &row = window.layout.rows[line];
@@ -587,6 +645,7 @@ int   main() {
             EndScissorMode();
         }
 
+        Dbg_Draw();
         EndDrawing();
     }
 }