[gtk+] gdk: Fix scissoring with scaled windows

[Alexander Larsson <alexl src gnome org>]

commit a1a01983f717a464e89ff2b569a5c61a2e3239c3
Author: Alexander Larsson <alexl redhat com>
Date:   Mon Dec 15 22:31:48 2014 +0100

    gdk: Fix scissoring with scaled windows
    
    Make sure the window scale is always taken into acount when setting up
    the scissor regions.

 gdk/gdkgl.c                |    8 ++++----
 gdk/x11/gdkglcontext-x11.c |   18 +++++++++---------
 2 files changed, 13 insertions(+), 13 deletions(-)
---
diff --git a/gdk/gdkgl.c b/gdk/gdkgl.c
index 67fafab..bc08bbc 100644
--- a/gdk/gdkgl.c
+++ b/gdk/gdkgl.c
@@ -702,11 +702,13 @@ gdk_gl_texture_from_surface (cairo_surface_t *surface,
 
   n_rects = cairo_region_num_rectangles (region);
 
+#define FLIP_Y(_y) (unscaled_window_height - (_y))
+
   for (i = 0; i < n_rects; i++)
     {
       cairo_region_get_rectangle (region, i, &rect);
 
-      glScissor (rect.x * window_scale, unscaled_window_height - (rect.y + rect.height) * window_scale,
+      glScissor (rect.x * window_scale, FLIP_Y ((rect.y + rect.height) * window_scale),
                  rect.width * window_scale, rect.height * window_scale);
 
       e = rect;
@@ -726,8 +728,6 @@ gdk_gl_texture_from_surface (cairo_surface_t *surface,
 
       cairo_surface_unmap_image (surface, image);
 
-#define FLIP_Y(_y) (unscaled_window_height - (_y))
-
       if (use_texture_rectangle)
         {
           umax = rect.width * sx;
@@ -741,7 +741,7 @@ gdk_gl_texture_from_surface (cairo_surface_t *surface,
 
       {
         GdkTexturedQuad quad = {
-          rect.x * window_scale, FLIP_Y(rect.y),
+          rect.x * window_scale, FLIP_Y(rect.y * window_scale),
           (rect.x + rect.width) * window_scale, FLIP_Y((rect.y + rect.height) * window_scale),
           0, 0,
           umax, vmax,
diff --git a/gdk/x11/gdkglcontext-x11.c b/gdk/x11/gdkglcontext-x11.c
index 566473a..d686768 100644
--- a/gdk/x11/gdkglcontext-x11.c
+++ b/gdk/x11/gdkglcontext-x11.c
@@ -424,7 +424,7 @@ gdk_x11_gl_context_texture_from_surface (GdkGLContext *paint_context,
   cairo_rectangle_int_t rect;
   int n_rects, i;
   GdkWindow *window;
-  int window_height;
+  int unscaled_window_height;
   int window_scale;
   unsigned int texture_id;
   gboolean use_texture_rectangle;
@@ -448,7 +448,7 @@ gdk_x11_gl_context_texture_from_surface (GdkGLContext *paint_context,
 
   window = gdk_gl_context_get_window (paint_context)->impl_window;
   window_scale = gdk_window_get_scale_factor (window);
-  window_height = gdk_window_get_height (window);
+  gdk_window_get_unscaled_size (window, NULL, &unscaled_window_height);
 
   sx = sy = 1;
   cairo_surface_get_device_scale (window->current_paint.surface, &sx, &sy);
@@ -476,11 +476,11 @@ gdk_x11_gl_context_texture_from_surface (GdkGLContext *paint_context,
   n_rects = cairo_region_num_rectangles (region);
   quads = g_new (GdkTexturedQuad, n_rects);
 
-#define FLIP_Y(_y) (window_height - (_y))
+#define FLIP_Y(_y) (unscaled_window_height - (_y))
 
   cairo_region_get_extents (region, &rect);
-  glScissor (rect.x * window_scale, FLIP_Y(rect.y) * window_scale,
-             (rect.x + rect.width) * window_scale, FLIP_Y (rect.y + rect.height) * window_scale);
+  glScissor (rect.x * window_scale, FLIP_Y((rect.y + rect.height) * window_scale),
+             rect.width * window_scale, rect.height * window_scale);
 
   for (i = 0; i < n_rects; i++)
     {
@@ -506,8 +506,8 @@ gdk_x11_gl_context_texture_from_surface (GdkGLContext *paint_context,
 
       {
         GdkTexturedQuad quad = {
-          rect.x * window_scale, FLIP_Y(rect.y) * window_scale,
-          (rect.x + rect.width) * window_scale, FLIP_Y(rect.y + rect.height) * window_scale,
+          rect.x * window_scale, FLIP_Y(rect.y * window_scale),
+          (rect.x + rect.width) * window_scale, FLIP_Y((rect.y + rect.height) * window_scale),
           uscale * src_x, vscale * src_y,
           uscale * (src_x + src_width), vscale * (src_y + src_height),
         };
@@ -518,11 +518,11 @@ gdk_x11_gl_context_texture_from_surface (GdkGLContext *paint_context,
 
 #undef FLIP_Y
 
-  glDisable (GL_SCISSOR_TEST);
-
   gdk_gl_texture_quads (paint_context, target, n_rects, quads);
   g_free (quads);
 
+  glDisable (GL_SCISSOR_TEST);
+
   glXReleaseTexImageEXT (glx_pixmap->display, glx_pixmap->drawable,
                         GLX_FRONT_LEFT_EXT);