Merge pull request #4 from tsoding/cursor

Cursor

main.c

@@ -78,6 +78,7 @@ Font font_load_from_file(SDL_Renderer *renderer, const char *file_path)
     Font font = {0};
 
     SDL_Surface *font_surface = surface_from_file(file_path);
+    scc(SDL_SetColorKey(font_surface, SDL_TRUE, 0xFF000000));
     font.spritesheet = scp(SDL_CreateTextureFromSurface(renderer, font_surface));
     SDL_FreeSurface(font_surface);
 
@@ -96,7 +97,7 @@ Font font_load_from_file(SDL_Renderer *renderer, const char *file_path)
     return font;
 }
 
-void render_char(SDL_Renderer *renderer, Font *font, char c, Vec2f pos, float scale)
+void render_char(SDL_Renderer *renderer, const Font *font, char c, Vec2f pos, float scale)
 {
     const SDL_Rect dst = {
         .x = (int) floorf(pos.x),
@@ -105,21 +106,28 @@ void render_char(SDL_Renderer *renderer, Font *font, char c, Vec2f pos, float sc
         .h = (int) floorf(FONT_CHAR_HEIGHT * scale),
     };
 
-    assert(c >= ASCII_DISPLAY_LOW);
-    assert(c <= ASCII_DISPLAY_HIGH);
-    const size_t index = c - ASCII_DISPLAY_LOW;
+    size_t index = '?' - ASCII_DISPLAY_LOW;
+    if (ASCII_DISPLAY_LOW <= c && c <= ASCII_DISPLAY_HIGH) {
+        index = c - ASCII_DISPLAY_LOW;
+    }
+
     scc(SDL_RenderCopy(renderer, font->spritesheet, &font->glyph_table[index], &dst));
 }
 
-void render_text_sized(SDL_Renderer *renderer, Font *font, const char *text, size_t text_size, Vec2f pos, Uint32 color, float scale)
+void set_texture_color(SDL_Texture *texture, Uint32 color)
 {
     scc(SDL_SetTextureColorMod(
-            font->spritesheet,
+            texture,
             (color >> (8 * 0)) & 0xff,
             (color >> (8 * 1)) & 0xff,
             (color >> (8 * 2)) & 0xff));
 
-    scc(SDL_SetTextureAlphaMod(font->spritesheet, (color >> (8 * 3)) & 0xff));
+    scc(SDL_SetTextureAlphaMod(texture, (color >> (8 * 3)) & 0xff));
+}
+
+void render_text_sized(SDL_Renderer *renderer, Font *font, const char *text, size_t text_size, Vec2f pos, Uint32 color, float scale)
+{
+    set_texture_color(font->spritesheet, color);
 
     Vec2f pen = pos;
     for (size_t i = 0; i < text_size; ++i) {
@@ -128,41 +136,88 @@ void render_text_sized(SDL_Renderer *renderer, Font *font, const char *text, siz
     }
 }
 
-void render_text(SDL_Renderer *renderer, Font *font, const char *text, Vec2f pos, Uint32 color, float scale)
-{
-    render_text_sized(renderer, font, text, strlen(text), pos, color, scale);
-}
-
 #define BUFFER_CAPACITY 1024
 
 char buffer[BUFFER_CAPACITY];
 size_t buffer_cursor = 0;
 size_t buffer_size = 0;
 
+void buffer_insert_text_before_cursor(const char *text)
+{
+    size_t text_size = strlen(text);
+    const size_t free_space = BUFFER_CAPACITY - buffer_size;
+    if (text_size > free_space) {
+        text_size = free_space;
+    }
+    memmove(buffer + buffer_cursor + text_size,
+            buffer + buffer_cursor,
+            buffer_size - buffer_cursor);
+    memcpy(buffer + buffer_cursor, text, text_size);
+    buffer_size += text_size;
+    buffer_cursor += text_size;
+}
+
+void buffer_backspace(void)
+{
+    if (buffer_cursor > 0 && buffer_size > 0) {
+        memmove(buffer + buffer_cursor - 1,
+                buffer + buffer_cursor,
+                buffer_size - buffer_cursor);
+        buffer_size -= 1;
+        buffer_cursor -= 1;
+    }
+}
+
+void buffer_delete(void)
+{
+    if (buffer_cursor < buffer_size && buffer_size > 0) {
+        memmove(buffer + buffer_cursor,
+                buffer + buffer_cursor + 1,
+                buffer_size - buffer_cursor);
+        buffer_size -= 1;
+    }
+}
+
 #define UNHEX(color) \
     ((color) >> (8 * 0)) & 0xFF, \
     ((color) >> (8 * 1)) & 0xFF, \
     ((color) >> (8 * 2)) & 0xFF, \
     ((color) >> (8 * 3)) & 0xFF
 
-void render_cursor(SDL_Renderer *renderer, Uint32 color)
+void render_cursor(SDL_Renderer *renderer, const Font *font)
 {
+    const Vec2f pos = vec2f((float) buffer_cursor * FONT_CHAR_WIDTH * FONT_SCALE, 0.0f);
+
     const SDL_Rect rect = {
-        .x = (int) floorf((float) buffer_cursor * FONT_CHAR_WIDTH * FONT_SCALE),
-        .y = 0,
+        .x = (int) floorf(pos.x),
+        .y = (int) floorf(pos.y),
         .w = FONT_CHAR_WIDTH * FONT_SCALE,
         .h = FONT_CHAR_HEIGHT * FONT_SCALE,
     };
 
-    scc(SDL_SetRenderDrawColor(renderer, UNHEX(color)));
+    scc(SDL_SetRenderDrawColor(renderer, UNHEX(0xFFFFFFFF)));
     scc(SDL_RenderFillRect(renderer, &rect));
+
+    set_texture_color(font->spritesheet, 0xFF000000);
+    if (buffer_cursor < buffer_size) {
+        render_char(renderer, font, buffer[buffer_cursor], pos, FONT_SCALE);
+    }
 }
 
+
+// TODO: Jump forward/backward by a word
+// TODO: Delete a word
+// TODO: Blinking cursor
+// TODO: Multiple lines
+// TODO: Save/Load file
+
 int main(int argc, char **argv)
 {
     (void) argc;
     (void) argv;
 
+    buffer_insert_text_before_cursor("Hello, World");
+
     scc(SDL_Init(SDL_INIT_VIDEO));
 
     SDL_Window *window =
@@ -188,9 +243,24 @@ int main(int argc, char **argv)
             case SDL_KEYDOWN: {
                 switch (event.key.keysym.sym) {
                 case SDLK_BACKSPACE: {
-                    if (buffer_size > 0) {
-                        buffer_size -= 1;
-                        buffer_cursor = buffer_size;
+                    buffer_backspace();
+                }
+                break;
+
+                case SDLK_DELETE: {
+                    buffer_delete();
+                } break;
+
+                case SDLK_LEFT: {
+                    if (buffer_cursor > 0) {
+                        buffer_cursor -= 1;
+                    }
+                }
+                break;
+
+                case SDLK_RIGHT: {
+                    if (buffer_cursor < buffer_size) {
+                        buffer_cursor += 1;
                     }
                 }
                 break;
@@ -199,14 +269,7 @@ int main(int argc, char **argv)
             break;
 
             case SDL_TEXTINPUT: {
-                size_t text_size = strlen(event.text.text);
-                const size_t free_space = BUFFER_CAPACITY - buffer_size;
-                if (text_size > free_space) {
-                    text_size = free_space;
-                }
-                memcpy(buffer + buffer_size, event.text.text, text_size);
-                buffer_size += text_size;
-                buffer_cursor = buffer_size;
+                buffer_insert_text_before_cursor(event.text.text);
             }
             break;
             }
@@ -216,7 +279,7 @@ int main(int argc, char **argv)
         scc(SDL_RenderClear(renderer));
 
         render_text_sized(renderer, &font, buffer, buffer_size, vec2f(0.0, 0.0), 0xFFFFFFFF, FONT_SCALE);
-        render_cursor(renderer, 0xFFFFFFFF);
+        render_cursor(renderer, &font);
 
         SDL_RenderPresent(renderer);
     }