add auto-scaling of UI depending on screen resolution - resolves #682

Sun, 15 Jun 2025 21:02:29 +0200

author
Mike Becker <universe@uap-core.de>
date
Sun, 15 Jun 2025 21:02:29 +0200
changeset 154
4dff9cc488fe
parent 153
4116e2bd501b
child 155
b598b4eb4b44

add auto-scaling of UI depending on screen resolution - resolves #682

src/ascension/context.h file | annotate | diff | comparison | revisions
src/ascension/ui.h file | annotate | diff | comparison | revisions
src/ascension/window.h file | annotate | diff | comparison | revisions
src/context.c file | annotate | diff | comparison | revisions
src/font.c file | annotate | diff | comparison | revisions
src/window.c file | annotate | diff | comparison | revisions
test/snake/snake.c file | annotate | diff | comparison | revisions
--- a/src/ascension/context.h	Sun Jun 15 19:50:51 2025 +0200
+++ b/src/ascension/context.h	Sun Jun 15 21:02:29 2025 +0200
@@ -61,7 +61,6 @@
     AscFont active_font;
     unsigned char active_window;
     asc_col4i ink;
-    float ui_scale;
     uint64_t frame_nanos;
     uint64_t total_nanos;
 } AscContext;
--- a/src/ascension/ui.h	Sun Jun 15 19:50:51 2025 +0200
+++ b/src/ascension/ui.h	Sun Jun 15 21:02:29 2025 +0200
@@ -30,12 +30,5 @@
 
 #include "ui/text.h"
 
-/**
- * Sets the UI scaling factor.
- * // TODO: think about whether this should be a context function which also triggers an update on all UI scenes
- * @param factor the scaling factor
- */
-#define asc_ui_scale(factor) asc_context.ui_scale = (factor)
-
 #endif /* ASCENSION_UI_H */
 
--- a/src/ascension/window.h	Sun Jun 15 19:50:51 2025 +0200
+++ b/src/ascension/window.h	Sun Jun 15 21:02:29 2025 +0200
@@ -58,6 +58,7 @@
     SDL_Window *window;
     asc_vec2u dimensions;
     AscGLContext glctx;
+    float ui_scale;
     AscScene ui;
     AscScene scenes[ASC_MAX_SCENES];
 } AscWindow;
@@ -140,6 +141,37 @@
  */
 AscScene *asc_window_scene(unsigned int index);
 
+/**
+ * The desktop display resolution related to the active window.
+ *
+ * @return the desktop display resolution of the display the active window is associated with
+ */
+asc_vec2u asc_window_display_resolution(void);
+
+// TODO: there is a ui.h - better move stuff there?
+
+/**
+ * Sets the UI scaling factor for the active window.
+ *
+ * @param scale the scaling factor
+ */
+void asc_ui_scale(float scale);
+
+/**
+ * Returns the current UI scaling factor for the active window.
+ *
+ * @return the scaling factor
+ */
+float asc_ui_get_scale(void);
+
+/**
+ * Automatically chooses a UI scaling factor depending on display resolution.
+ *
+ * @note you need to call this function again when the window changes the display
+ * // TODO: check if there is an SDL event when the window changes the display and implement a reaction
+ */
+void asc_ui_scale_auto(void);
+
 void asc_add_ui_node(AscSceneNode *node);
 
 #endif /* ASCENSION_WINDOW_H */
--- a/src/context.c	Sun Jun 15 19:50:51 2025 +0200
+++ b/src/context.c	Sun Jun 15 21:02:29 2025 +0200
@@ -65,9 +65,6 @@
     asc_context.active_font.style = ASC_FONT_REGULAR;
     asc_context.active_font.size = 14;
 
-    // default UI scale
-    asc_context.ui_scale = 1.0f;
-
     // no window, yet
     asc_context.active_window = ASC_MAX_WINDOWS;
 
--- a/src/font.c	Sun Jun 15 19:50:51 2025 +0200
+++ b/src/font.c	Sun Jun 15 21:02:29 2025 +0200
@@ -82,8 +82,9 @@
 
 TTF_Font *asc_font_load(AscFont font) {
     // apply the UI scaling factor first to get the actual font size
-    if (asc_context.ui_scale != 1.f) {
-        font.size = (int) roundf((float) font.size * asc_context.ui_scale);
+    const float ui_scale = asc_active_window->ui_scale;
+    if (ui_scale != 1.f) {
+        font.size = (int) roundf((float) font.size * ui_scale);
     }
 
     CxIterator iter = cxListIterator(asc_font_cache);
--- a/src/window.c	Sun Jun 15 19:50:51 2025 +0200
+++ b/src/window.c	Sun Jun 15 21:02:29 2025 +0200
@@ -77,6 +77,9 @@
     }
     window->resized = true; // count initial sizing as resize
 
+    // default UI scale
+    window->ui_scale = 1.0f;
+
     if (asc_gl_context_initialize(&window->glctx, window->window, &settings->glsettings)) {
         asc_scene_init(&window->ui,
             .type = ASC_CAMERA_ORTHO,
@@ -198,3 +201,34 @@
 AscScene *asc_window_scene(unsigned int index) {
     return &asc_active_window->scenes[index];
 }
+
+asc_vec2u asc_window_display_resolution(void) {
+    const AscWindow *window = asc_active_window;
+    SDL_DisplayMode dm;
+    const int display = SDL_GetWindowDisplayIndex(window->window);
+    if (SDL_GetDesktopDisplayMode(display, &dm)) {
+        asc_error("Failed to get display mode for window %u on display %d: %s",
+            window->id, display, SDL_GetError());
+    }
+    return asc_vec2u_new(dm.w, dm.h);
+}
+
+void asc_ui_scale(float scale) {
+    asc_active_window->ui_scale = scale;
+}
+
+float asc_ui_get_scale(void) {
+    return asc_active_window->ui_scale;
+}
+
+void asc_ui_scale_auto(void) {
+    asc_vec2u res = asc_window_display_resolution();
+    // TODO: debug why this is wrong under GNOME or just throw GNOME away
+    if (res.width > 3000) {
+        asc_ui_scale(1.5f);
+    } else if (res.width > 2000) {
+        asc_ui_scale(1.2f);
+    } else {
+        return asc_ui_scale(1.f);
+    }
+}
--- a/test/snake/snake.c	Sun Jun 15 19:50:51 2025 +0200
+++ b/test/snake/snake.c	Sun Jun 15 21:02:29 2025 +0200
@@ -167,6 +167,7 @@
     asc_window_settings_init_defaults(&settings);
     settings.title = "Snake";
     asc_window_initialize(0, &settings);
+    asc_ui_scale_auto();
 
     // load textures
     init_textures();

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