[gnome-games/wip/exalm/hidpi: 6/7] savestate-listbox-row: Support hidpi thumbnails

[Alexander Mikhaylenko <alexm src gnome org>]

commit 3f5dcc22e0d0ac72d929f5b12fceb0bcaa78ebad
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Sat Aug 17 01:49:57 2019 +0500

    savestate-listbox-row: Support hidpi thumbnails
    
    Load the pixbuf with higher resolution, then downscale it when drawing.
    
    This ensures the thumbnails are still crisp on hidpi.

 src/ui/savestate-listbox-row.vala | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)
---
diff --git a/src/ui/savestate-listbox-row.vala b/src/ui/savestate-listbox-row.vala
index 16fc057c..cc606f17 100644
--- a/src/ui/savestate-listbox-row.vala
+++ b/src/ui/savestate-listbox-row.vala
@@ -58,6 +58,9 @@ private class Games.SavestateListBoxRow : Gtk.ListBoxRow {
                                thumbnail_width = (int) (THUMBNAIL_SIZE * aspect_ratio);
                        }
 
+                       thumbnail_width *= scale_factor;
+                       thumbnail_height *= scale_factor;
+
                        try {
                                pixbuf = new Gdk.Pixbuf.from_file_at_scale (screenshot_path,
                                                                            thumbnail_width,
@@ -102,33 +105,40 @@ private class Games.SavestateListBoxRow : Gtk.ListBoxRow {
                style.render_background (cr, 0.0, 0.0, width, height);
                style.render_frame (cr, 0.0, 0.0, width, height);
 
+               cr.save ();
+               cr.scale (1.0 / scale_factor, 1.0 / scale_factor);
+
                var mask = get_mask ();
 
                var surface = Gdk.cairo_surface_create_from_pixbuf (pixbuf, 1, image.get_window ());
-               var x_offset = (width - pixbuf.width) / 2;
-               var y_offset = (height - pixbuf.height) / 2;
+               var x_offset = (width * scale_factor - pixbuf.width) / 2;
+               var y_offset = (height * scale_factor - pixbuf.height) / 2;
 
                cr.set_source_surface (surface, x_offset, y_offset);
+
                cr.mask_surface (mask, 0, 0);
 
+               cr.restore ();
+
                return Gdk.EVENT_PROPAGATE;
        }
 
        // TODO: Share this with GameThumbnail
        private Cairo.Surface get_mask () {
+               var scale = scale_factor;
                var width = image.get_allocated_width ();
                var height = image.get_allocated_height ();
 
-               var mask = new Cairo.ImageSurface (Cairo.Format.A8, width, height);
+               var mask = new Cairo.ImageSurface (Cairo.Format.A8, width * scale, height * scale);
 
                var style = image.get_style_context ();
                var flags = image.get_state_flags ();
-               var border_radius = (int) style.get_property (Gtk.STYLE_PROPERTY_BORDER_RADIUS, flags);
-               border_radius = border_radius.clamp (0, int.max (width / 2, height / 2));
+               var border_radius = (int) style.get_property (Gtk.STYLE_PROPERTY_BORDER_RADIUS, flags) * 
scale;
+               border_radius = border_radius.clamp (0, int.max (width * scale / 2, height * scale / 2));
 
                var cr = new Cairo.Context (mask);
                cr.set_source_rgb (0, 0, 0);
-               rounded_rectangle (cr, 0.5, 0.5, width - 1, height - 1, border_radius);
+               rounded_rectangle (cr, 0.5 * scale, 0.5 * scale, (width - 1) * scale, (height - 1) * scale, 
border_radius);
                cr.fill ();
 
                return mask;