X scrolling using main cursor

src/text_editor/main.cpp

@@ -3,6 +3,8 @@
 #include "raylib.h"
 #include "raymath.h"
 
+// @todo: add history (undo, redo)
+// @todo: add clipboard history?
 #include "buffer.cpp"
 #include "rect2.cpp"
 
@@ -78,6 +80,46 @@ void DrawString(Font font, String text, Vector2 position, float fontSize, float
     }
 }
 
+Vector2 MeasureString(Font font, String text, float fontSize, float spacing) {
+    Vector2 textSize = {0};
+    if ((font.texture.id == 0) || (text.data == NULL)) return textSize; // Security check
+
+    int size            = (int)text.len; // Get size in bytes of text
+    int tempByteCounter = 0;             // Used to count longer text line num chars
+    int byteCounter     = 0;
+
+    float textWidth     = 0.0f;
+    float tempTextWidth = 0.0f; // Used to count longer text line width
+
+    float textHeight  = fontSize;
+    float scaleFactor = fontSize / (float)font.baseSize;
+
+    int letter = 0; // Current character
+    int index  = 0; // Index position in sprite font
+
+    for (int i = 0; i < size;) {
+        byteCounter++;
+
+        int next = 0;
+        letter   = GetCodepointNext(&text.data[i], &next);
+        index    = GetGlyphIndex(font, letter);
+
+        i += next;
+
+        if (font.glyphs[index].advanceX != 0) textWidth += font.glyphs[index].advanceX;
+        else textWidth += (font.recs[index].width + font.glyphs[index].offsetX);
+
+        if (tempByteCounter < byteCounter) tempByteCounter = byteCounter;
+    }
+
+    if (tempTextWidth < textWidth) tempTextWidth = textWidth;
+
+    textSize.x = tempTextWidth * scaleFactor + (float)((tempByteCounter - 1) * spacing);
+    textSize.y = textHeight;
+
+    return textSize;
+}
+
 int64_t MoveRight(Buffer &buffer, int64_t pos) {
     pos = pos + 1;
     pos = AdjustUTF8Pos(buffer, pos);
@@ -182,7 +224,7 @@ int   main() {
         if (1) {
             for (int i = 0; i < 50; i += 1) {
                 Array<Edit> edits = {FrameArena};
-                AddEdit(&edits, GetEnd(window.buffer), Format(FrameArena, "line number: %d\n", i));
+                AddEdit(&edits, GetEnd(window.buffer), Format(FrameArena, "line number sddddddddddddssssssssss faasda s: %d\n", i));
                 ApplyEdits(&window.buffer, edits);
             }
         }
@@ -559,27 +601,45 @@ int   main() {
                     if (row.cells.len) rows.add(row);
                 }
             }
-            Assert(rows.len);
 
-            // @todo: x axis
             // 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);
+                Cursor  cursor = window.cursors[0];
+                int64_t front  = GetFront(cursor);
+                Line    line   = FindLine(window.buffer, front);
+
+                // Scroll Y
                 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;
                 }
+
+                // Scroll X
+                Range  x_distance        = {line.range.min, front};
+                String x_distance_string = GetString(window.buffer, x_distance);
+                Vec2   size              = MeasureString(font, x_distance_string, font_size, font_spacing);
+                if (x_distance_string.len <= 0) size.x = 0;
+                float x_cursor_position_in_window_buffer_world_units = size.x;
+
+                GlyphInfo info                           = GetGlyphInfo(font, ' ');
+                float     right_scroll_zone              = (float)(info.image.width + info.advanceX) * 3;
+                float     window_buffer_world_right_edge = (rect_in_render_units.x + window.scroll.x) - right_scroll_zone;
+                float     window_buffer_world_left_edge  = window.scroll.x;
+                if (x_cursor_position_in_window_buffer_world_units >= window_buffer_world_right_edge) {
+                    float diff = x_cursor_position_in_window_buffer_world_units - window_buffer_world_right_edge;
+                    window.scroll.x += diff;
+                } else if (x_cursor_position_in_window_buffer_world_units <= window_buffer_world_left_edge) {
+                    float diff = x_cursor_position_in_window_buffer_world_units - window_buffer_world_left_edge;
+                    window.scroll.x += diff;
+                }
             }
 
             // Draw debug markers