wayland: Read GDK_SCALE

This is somewhat disappointing, because the
surface size stays the same, just the rendering
changes.

gdk/gdkglcontext.c

@@ -94,6 +94,8 @@
 #include <epoxy/egl.h>
 #endif
 
+#include <math.h>
+
 #define DEFAULT_ALLOWED_APIS GDK_GL_API_GL | GDK_GL_API_GLES
 
 typedef struct {
@@ -586,8 +588,8 @@ gdk_gl_context_real_begin_frame (GdkDrawContext *draw_context,
   cairo_region_union (region, damage);
   cairo_region_destroy (damage);
 
-  ww = gdk_surface_get_width (surface) * gdk_surface_get_scale_factor (surface);
+  ww = (int) ceil (gdk_surface_get_width (surface) * gdk_surface_get_scale (surface));
-  wh = gdk_surface_get_height (surface) * gdk_surface_get_scale_factor (surface);
+  wh = (int) ceil (gdk_surface_get_height (surface) * gdk_surface_get_scale (surface));
 
   gdk_gl_context_make_current (context);
 
@@ -631,7 +633,7 @@ gdk_gl_context_real_end_frame (GdkDrawContext *draw_context,
       EGLint *heap_rects = NULL;
       int i, j, n_rects = cairo_region_num_rectangles (painted);
       int surface_height = gdk_surface_get_height (surface);
-      int scale = gdk_surface_get_scale_factor (surface);
+      double scale = gdk_surface_get_scale (surface);
       EGLint *rects;
 
       if (n_rects < G_N_ELEMENTS (stack_rects) / 4)
@@ -644,10 +646,10 @@ gdk_gl_context_real_end_frame (GdkDrawContext *draw_context,
           cairo_rectangle_int_t rect;
 
           cairo_region_get_rectangle (painted, i, &rect);
-          rects[j++] = rect.x * scale;
+          rects[j++] = (int) floor (rect.x * scale);
-          rects[j++] = (surface_height - rect.height - rect.y) * scale;
+          rects[j++] = (int) floor ((surface_height - rect.height - rect.y) * scale);
-          rects[j++] = rect.width * scale;
+          rects[j++] = (int) ceil (rect.width * scale);
-          rects[j++] = rect.height * scale;
+          rects[j++] = (int) ceil (rect.height * scale);
         }
       priv->eglSwapBuffersWithDamage (gdk_display_get_egl_display (display), egl_surface, rects, n_rects);
       g_free (heap_rects);

gdk/wayland/gdkprivate-wayland.h

@@ -58,6 +58,7 @@ struct _GdkFractionalScale
 
 #define GDK_FRACTIONAL_SCALE_INIT(fractional_scale) (GdkFractionalScale) { fractional_scale }
 #define GDK_FRACTIONAL_SCALE_INIT_INT(scale) GDK_FRACTIONAL_SCALE_INIT (scale * GDK_FRACTIONAL_SCALE_FACTOR)
+#define GDK_FRACTIONAL_SCALE_INIT_FLOAT(scale) GDK_FRACTIONAL_SCALE_INIT ((int) (scale * GDK_FRACTIONAL_SCALE_FACTOR))
 
 static inline int
 gdk_fractional_scale_to_int (const GdkFractionalScale *self)

gdk/wayland/gdksurface-wayland-private.h

@@ -48,6 +48,7 @@ struct _GdkWaylandSurface
   unsigned int mapped : 1;
   unsigned int awaiting_frame : 1;
   unsigned int awaiting_frame_frozen : 1;
+  unsigned int scale_overridden : 1;
 
   int pending_buffer_offset_x;
   int pending_buffer_offset_y;

gdk/wayland/gdksurface-wayland.c

@@ -172,6 +172,31 @@ gdk_wayland_surface_init (GdkWaylandSurface *impl)
 {
   impl->scale = GDK_FRACTIONAL_SCALE_INIT_INT (1);
   impl->viewport_dirty = TRUE;
+
+  if (g_getenv ("GDK_SCALE"))
+    {
+      const char *scale_str;
+      char *endptr = NULL;
+      double scale;
+
+      scale_str = g_getenv ("GDK_SCALE");
+
+      scale = g_ascii_strtod (scale_str, &endptr);
+
+      if (endptr && *endptr != '\0')
+        {
+          if (strcmp (endptr, "%") == 0)
+            scale /= 100.;
+          else
+            {
+              g_warning ("Failed to parse GDK_SCALE");
+              return;
+            }
+        }
+
+      impl->scale = GDK_FRACTIONAL_SCALE_INIT_FLOAT (scale);
+      impl->scale_overridden = TRUE;
+    }
 }
 
 void
@@ -259,8 +284,9 @@ gdk_wayland_surface_update_size (GdkSurface               *surface,
 
   if (impl->display_server.egl_window)
     wl_egl_window_resize (impl->display_server.egl_window,
-                          width * gdk_fractional_scale_to_int (scale),
+                          gdk_fractional_scale_scale (scale, width),
-                          height * gdk_fractional_scale_to_int (scale), 0, 0);
+                          gdk_fractional_scale_scale (scale, height),
+                          0, 0);
 
   gdk_surface_invalidate_rect (surface, NULL);
 
@@ -463,6 +489,9 @@ gdk_wayland_surface_update_scale (GdkSurface *surface)
       wl_surface_get_version (impl->display_server.wl_surface) < WL_SURFACE_SET_BUFFER_SCALE_SINCE_VERSION)
     return;
 
+  if (impl->scale_overridden)
+    return;
+
   /* scale is tracked by the fractional scale extension */
   if (impl->display_server.fractional_scale)
     return;
@@ -831,6 +860,9 @@ gdk_wayland_surface_fractional_scale_preferred_scale_cb (void *data,
   GdkWaylandSurface *self = GDK_WAYLAND_SURFACE (data);
   GdkSurface *surface = GDK_SURFACE (self);
 
+  if (self->scale_overridden)
+    return;
+
   /* Notify app that scale changed */
   gdk_wayland_surface_maybe_resize (surface,
                                     surface->width, surface->height,
@@ -1364,8 +1396,8 @@ gdk_wayland_surface_ensure_wl_egl_window (GdkSurface *surface)
     {
       impl->display_server.egl_window =
         wl_egl_window_create (impl->display_server.wl_surface,
-                              surface->width * gdk_fractional_scale_to_int (&impl->scale),
+                              gdk_fractional_scale_scale (&impl->scale, surface->width),
-                              surface->height * gdk_fractional_scale_to_int (&impl->scale));
+                              gdk_fractional_scale_scale (&impl->scale, surface->height));
       gdk_surface_set_egl_native_window (surface, impl->display_server.egl_window);
     }
 }

gsk/gl/gskglcommandqueue.c

@@ -993,7 +993,7 @@ gsk_gl_command_queue_sort_batches (GskGLCommandQueue *self)
  * gsk_gl_command_queue_execute:
  * @self: a `GskGLCommandQueue`
  * @surface_height: the height of the backing surface
- * @scale_factor: the scale factor of the backing surface
+ * @scale: the scale of the backing surface
  * @scissor: (nullable): the scissor clip if any
  * @default_framebuffer: the default framebuffer id if not zero
  *
@@ -1009,7 +1009,7 @@ gsk_gl_command_queue_sort_batches (GskGLCommandQueue *self)
 void
 gsk_gl_command_queue_execute (GskGLCommandQueue    *self,
                               guint                 surface_height,
-                              guint                 scale_factor,
+                              float                 scale,
                               const cairo_region_t *scissor,
                               guint                 default_framebuffer)
 {
@@ -1097,10 +1097,10 @@ gsk_gl_command_queue_execute (GskGLCommandQueue    *self,
       g_assert (cairo_region_num_rectangles (scissor) == 1);
       cairo_region_get_rectangle (scissor, 0, &r);
 
-      scissor_test.origin.x = r.x * scale_factor;
+      scissor_test.origin.x = (int) floor (r.x * scale);
-      scissor_test.origin.y = surface_height - (r.height * scale_factor) - (r.y * scale_factor);
+      scissor_test.origin.y = (int) floor (surface_height - (r.height * scale) - (r.y * scale));
-      scissor_test.size.width = r.width * scale_factor;
+      scissor_test.size.width = (int) ceil (r.width * scale);
-      scissor_test.size.height = r.height * scale_factor;
+      scissor_test.size.height = (int) ceil (r.height * scale);
     }
 
   next_batch_index = self->head_batch_index;

gsk/gl/gskglcommandqueueprivate.h

@@ -288,7 +288,7 @@ void                gsk_gl_command_queue_begin_frame          (GskGLCommandQueue
 void                gsk_gl_command_queue_end_frame            (GskGLCommandQueue    *self);
 void                gsk_gl_command_queue_execute              (GskGLCommandQueue    *self,
                                                                guint                 surface_height,
-                                                               guint                 scale_factor,
+                                                               float                 scale,
                                                                const cairo_region_t *scissor,
                                                                guint                 default_framebuffer);
 int                 gsk_gl_command_queue_upload_texture       (GskGLCommandQueue    *self,

gsk/gl/gskglrenderer.c

@@ -282,18 +282,18 @@ gsk_gl_renderer_render (GskRenderer          *renderer,
   GskGLRenderJob *job;
   GdkSurface *surface;
   gboolean clear_framebuffer;
-  float scale_factor;
+  float scale;
 
   g_assert (GSK_IS_GL_RENDERER (renderer));
   g_assert (root != NULL);
 
   surface = gdk_draw_context_get_surface (GDK_DRAW_CONTEXT (self->context));
-  scale_factor = gdk_surface_get_scale_factor (surface);
+  scale = gdk_surface_get_scale (surface);
 
   viewport.origin.x = 0;
   viewport.origin.y = 0;
-  viewport.size.width = gdk_surface_get_width (surface) * scale_factor;
+  viewport.size.width = gdk_surface_get_width (surface) * scale;
-  viewport.size.height = gdk_surface_get_height (surface) * scale_factor;
+  viewport.size.height = gdk_surface_get_height (surface) * scale;
 
   gdk_draw_context_begin_frame_full (GDK_DRAW_CONTEXT (self->context),
                                      gsk_render_node_prefers_high_depth (root),
@@ -306,7 +306,7 @@ gsk_gl_renderer_render (GskRenderer          *renderer,
   clear_framebuffer = update_area_requires_clear (surface, render_region);
 
   gsk_gl_driver_begin_frame (self->driver, self->command_queue);
-  job = gsk_gl_render_job_new (self->driver, &viewport, scale_factor, render_region, 0, clear_framebuffer);
+  job = gsk_gl_render_job_new (self->driver, &viewport, scale, render_region, 0, clear_framebuffer);
 #ifdef G_ENABLE_DEBUG
   if (GSK_RENDERER_DEBUG_CHECK (GSK_RENDERER (self), FALLBACK))
     gsk_gl_render_job_set_debug_fallback (job, TRUE);

gsk/gl/gskglrenderjob.c

@@ -4322,14 +4322,14 @@ gsk_gl_render_job_render (GskGLRenderJob *job,
                           GskRenderNode  *root)
 {
   G_GNUC_UNUSED gint64 start_time;
-  guint scale_factor;
+  float scale;
   guint surface_height;
 
   g_return_if_fail (job != NULL);
   g_return_if_fail (root != NULL);
   g_return_if_fail (GSK_IS_GL_DRIVER (job->driver));
 
-  scale_factor = MAX (job->scale_x, job->scale_y);
+  scale = MAX (job->scale_x, job->scale_y);
   surface_height = job->viewport.size.height;
 
   gsk_gl_command_queue_make_current (job->command_queue);
@@ -4360,7 +4360,7 @@ gsk_gl_render_job_render (GskGLRenderJob *job,
   start_time = GDK_PROFILER_CURRENT_TIME;
   gsk_gl_command_queue_make_current (job->command_queue);
   gdk_gl_context_push_debug_group (job->command_queue->context, "Executing command queue");
-  gsk_gl_command_queue_execute (job->command_queue, surface_height, scale_factor, job->region, job->default_framebuffer);
+  gsk_gl_command_queue_execute (job->command_queue, surface_height, scale, job->region, job->default_framebuffer);
   gdk_gl_context_pop_debug_group (job->command_queue->context);
   gdk_profiler_add_mark (start_time, GDK_PROFILER_CURRENT_TIME-start_time, "Execute GL command queue", "");
 }
@@ -4401,7 +4401,7 @@ get_framebuffer_format (GdkGLContext *context,
 GskGLRenderJob *
 gsk_gl_render_job_new (GskGLDriver           *driver,
                        const graphene_rect_t *viewport,
-                       float                  scale_factor,
+                       float                  scale,
                        const cairo_region_t  *region,
                        guint                  framebuffer,
                        gboolean               clear_framebuffer)
@@ -4414,7 +4414,7 @@ gsk_gl_render_job_new (GskGLDriver           *driver,
 
   g_return_val_if_fail (GSK_IS_GL_DRIVER (driver), NULL);
   g_return_val_if_fail (viewport != NULL, NULL);
-  g_return_val_if_fail (scale_factor > 0, NULL);
+  g_return_val_if_fail (scale > 0, NULL);
 
   /* Check for non-standard framebuffer binding as we might not be using
    * the default framebuffer on systems like macOS where we've bound an
@@ -4436,14 +4436,14 @@ gsk_gl_render_job_new (GskGLDriver           *driver,
   job->default_framebuffer = default_framebuffer;
   job->offset_x = 0;
   job->offset_y = 0;
-  job->scale_x = scale_factor;
+  job->scale_x = scale;
-  job->scale_y = scale_factor;
+  job->scale_y = scale;
   job->viewport = *viewport;
   job->target_format = get_framebuffer_format (job->command_queue->context, framebuffer);
 
   gsk_gl_render_job_set_alpha (job, 1.0f);
   gsk_gl_render_job_set_projection_from_rect (job, viewport, NULL);
-  gsk_gl_render_job_set_modelview (job, gsk_transform_scale (NULL, scale_factor, scale_factor));
+  gsk_gl_render_job_set_modelview (job, gsk_transform_scale (NULL, scale, scale));
 
   /* Setup our initial clip. If region is NULL then we are drawing the
    * whole viewport. Otherwise, we need to convert the region to a

gsk/gl/gskglrenderjobprivate.h

@@ -24,7 +24,7 @@
 
 GskGLRenderJob *gsk_gl_render_job_new                (GskGLDriver           *driver,
                                                       const graphene_rect_t *viewport,
-                                                      float                  scale_factor,
+                                                      float                  scale,
                                                       const cairo_region_t  *region,
                                                       guint                  framebuffer,
                                                       gboolean               clear_framebuffer);