[shotwell/wip/transparent-background: 2/2] WIP

[Jens Georg <jensgeorg src gnome org>]

commit 7b9a68e61a12588a9e56163901eedd0a96392024
Author: Jens Georg <mail jensge org>
Date:   Thu Apr 20 22:00:25 2017 +0200

    WIP

 src/Page.vala |   87 ++++++++++++++++----------------------------------------
 1 files changed, 25 insertions(+), 62 deletions(-)
---
diff --git a/src/Page.vala b/src/Page.vala
index b5eb953..17efb7c 100644
--- a/src/Page.vala
+++ b/src/Page.vala
@@ -2061,24 +2061,7 @@ public abstract class SinglePhotoPage : Page {
         int draw_y = (pixmap_dim.height - view_rect.height) / 2;
         draw_y = draw_y.clamp(0, int.MAX);
         if (zoomed.get_has_alpha()) {
-            if (background_surface == null) {
-                background_surface = get_window().create_similar_surface(Cairo.Content.COLOR_ALPHA,
-                    16, 16);
-                var ctx2 = new Cairo.Context(background_surface);
-                ctx2.set_operator(Cairo.Operator.SOURCE);
-                set_source_color_from_string(ctx2, "#808080");
-                ctx2.rectangle(0,0,8,8);
-                ctx2.rectangle(8,8,8,8);
-                ctx2.fill();
-                set_source_color_from_string(ctx2, "#cccccc");
-                ctx2.rectangle(0,8,8,8);
-                ctx2.rectangle(8,0,8,8);
-                ctx2.fill();
-            }
-
-            warning ("\n=====================> dkdkjdkjdkjdkj\n");
-
-            pixmap_ctx.set_source_surface(background_surface, 0, 0);
+            pixmap_ctx.set_source_surface(get_background_surface(), 0, 0);
             pixmap_ctx.get_source().set_extend(Cairo.Extend.REPEAT);
             pixmap_ctx.rectangle(draw_x, draw_y,
                                 zoomed.width,
@@ -2275,34 +2258,12 @@ public abstract class SinglePhotoPage : Page {
         repaint();
     }
 
-    private Cairo.Surface? background_surface = null;
-    
     private bool on_canvas_exposed(Cairo.Context exposed_ctx) {
         // draw pixmap onto canvas unless it's not been instantiated, in which case draw black
         // (so either old image or contents of another page is not left on screen)
-        if (pixmap != null) {
-            /*if (pixmap.has_alpha)*/ {
-                if (background_surface == null) {
-                    background_surface = get_window().create_similar_surface(Cairo.Content.COLOR_ALPHA,
-                    16, 16);
-                    var ctx = new Cairo.Context(background_surface);
-                    ctx.set_operator(Cairo.Operator.SOURCE);
-                    set_source_color_from_string(ctx, "#808080");
-                    ctx.rectangle(0,0,8,8);
-                    ctx.rectangle(8,8,8,8);
-                    ctx.fill();
-                    set_source_color_from_string(ctx, "#cccccc");
-                    ctx.rectangle(0,8,8,8);
-                    ctx.rectangle(8,0,8,8);
-                    ctx.fill();
-                }
-                exposed_ctx.set_source_surface(background_surface, 0, 0);
-                exposed_ctx.get_source().set_extend(Cairo.Extend.REPEAT);
-                exposed_ctx.rectangle(0, 0, get_allocated_width(), get_allocated_height());
-                exposed_ctx.paint();
-            }
+        if (pixmap != null)
             exposed_ctx.set_source_surface(pixmap, 0, 0);
-        } else
+        else
             set_source_color_from_string(exposed_ctx, "#000");
         
         exposed_ctx.rectangle(0, 0, get_allocated_width(), get_allocated_height());
@@ -2316,6 +2277,27 @@ public abstract class SinglePhotoPage : Page {
     
     protected virtual void updated_pixbuf(Gdk.Pixbuf pixbuf, UpdateReason reason, Dimensions old_dim) {
     }
+
+    private Cairo.Surface background_surface = null;
+
+    protected Cairo.Surface get_background_surface() {
+        if (background_surface == null) {
+            var window = get_window();
+            background_surface = window.create_similar_surface(Cairo.Content.COLOR_ALPHA, 16, 16);
+            var ctx = new Cairo.Context(background_surface);
+            ctx.set_operator(Cairo.Operator.SOURCE);
+            set_source_color_from_string(ctx, "#808080");
+            ctx.rectangle(0,0,8,8);
+            ctx.rectangle(8,8,8,8);
+            ctx.fill();
+            set_source_color_from_string(ctx, "#cccccc");
+            ctx.rectangle(0,8,8,8);
+            ctx.rectangle(8,0,8,8);
+            ctx.fill();
+        }
+
+        return background_surface;
+    }
     
     protected virtual void paint(Cairo.Context ctx, Dimensions ctx_dim) {
         if (is_zoom_supported() && (!static_zoom_state.is_default())) {
@@ -2331,27 +2313,8 @@ public abstract class SinglePhotoPage : Page {
             ctx.rectangle(0, 0, pixmap_dim.width, pixmap_dim.height);
             ctx.fill();
 
-            warning ("\n====> scaled %d %d %d %d\n", scaled_pos.x,
-                    scaled_pos.y,
-                    scaled.width, scaled.height);
-
             if (scaled.has_alpha) {
-                if (background_surface == null) {
-                    background_surface = get_window().create_similar_surface(Cairo.Content.COLOR_ALPHA,
-                            16, 16);
-                    var ctx2 = new Cairo.Context(background_surface);
-                    ctx2.set_operator(Cairo.Operator.SOURCE);
-                    set_source_color_from_string(ctx2, "#808080");
-                    ctx2.rectangle(0,0,8,8);
-                    ctx2.rectangle(8,8,8,8);
-                    ctx2.fill();
-                    set_source_color_from_string(ctx2, "#cccccc");
-                    ctx2.rectangle(0,8,8,8);
-                    ctx2.rectangle(8,0,8,8);
-                    ctx2.fill();
-                }
-
-                ctx.set_source_surface(background_surface, 0, 0);
+                ctx.set_source_surface(get_background_surface(), 0, 0);
                 ctx.get_source().set_extend(Cairo.Extend.REPEAT);
                 ctx.rectangle(scaled_pos.x, scaled_pos.y,
                         scaled.width,