Add support for copying to clipboard

So far, the macOS special casing is only partial.

Also, GtkShortcutsWindow confusingly labels Command as Meta.

fiv-view.c

@@ -990,6 +990,34 @@ get_toplevel(GtkWidget *widget)
 	return NULL;
 }
 
+static void
+copy(FivView *self)
+{
+	double fractional_width = 0, fractional_height = 0;
+	cairo_matrix_t matrix = fiv_io_orientation_apply(
+		self->frame, self->orientation, &fractional_width, &fractional_height);
+	int w = ceil(fractional_width), h = ceil(fractional_height);
+
+	// XXX: SVG is rendered pre-scaled.
+	cairo_surface_t *transformed =
+		cairo_image_surface_create(CAIRO_FORMAT_ARGB32, w, h);
+	cairo_t *cr = cairo_create(transformed);
+	cairo_set_source_surface(cr, self->frame, 0, 0);
+	cairo_pattern_set_matrix(cairo_get_source(cr), &matrix);
+	cairo_paint(cr);
+	cairo_destroy(cr);
+
+	// TODO(p): Use 16-bit PNGs for >8-bit Cairo surfaces: PNG-encode them
+	// ourselves and fall back to gtk_selection_data_set_pixbuf().
+	GdkPixbuf *pixbuf = gdk_pixbuf_get_from_surface(transformed, 0, 0, w, h);
+	cairo_surface_destroy(transformed);
+	gtk_clipboard_set_image(
+		gtk_clipboard_get_for_display(
+			gtk_widget_get_display(GTK_WIDGET(self)), GDK_SELECTION_CLIPBOARD),
+		pixbuf);
+	g_object_unref(pixbuf);
+}
+
 static void
 on_draw_page(G_GNUC_UNUSED GtkPrintOperation *operation,
 	GtkPrintContext *context, G_GNUC_UNUSED int page_nr, FivView *self)
@@ -1419,14 +1447,19 @@ fiv_view_class_init(FivViewClass *klass)
 	widget_class->scroll_event = fiv_view_scroll_event;
 	widget_class->key_press_event = fiv_view_key_press_event;
 
+	// _gtk_get_primary_accel_mod() is private.
+	GdkModifierType primary = GDK_CONTROL_MASK;
+	gtk_accelerator_parse_with_keycode("<Primary>", NULL, NULL, &primary);
+
 	GtkBindingSet *bs = gtk_binding_set_by_class(klass);
 	// First, the standard, intuitive bindings.
-	bind(bs, GDK_KEY_0,      GDK_CONTROL_MASK, FIV_VIEW_COMMAND_ZOOM_1);
+	bind(bs, GDK_KEY_0,      primary,       FIV_VIEW_COMMAND_ZOOM_1);
-	bind(bs, GDK_KEY_plus,   GDK_CONTROL_MASK, FIV_VIEW_COMMAND_ZOOM_IN);
+	bind(bs, GDK_KEY_plus,   primary,       FIV_VIEW_COMMAND_ZOOM_IN);
-	bind(bs, GDK_KEY_minus,  GDK_CONTROL_MASK, FIV_VIEW_COMMAND_ZOOM_OUT);
+	bind(bs, GDK_KEY_minus,  primary,       FIV_VIEW_COMMAND_ZOOM_OUT);
-	bind(bs, GDK_KEY_p,      GDK_CONTROL_MASK, FIV_VIEW_COMMAND_PRINT);
+	bind(bs, GDK_KEY_c,      primary,       FIV_VIEW_COMMAND_COPY);
-	bind(bs, GDK_KEY_r,      GDK_CONTROL_MASK, FIV_VIEW_COMMAND_RELOAD);
+	bind(bs, GDK_KEY_p,      primary,       FIV_VIEW_COMMAND_PRINT);
-	bind(bs, GDK_KEY_s,      GDK_CONTROL_MASK, FIV_VIEW_COMMAND_SAVE_PAGE);
+	bind(bs, GDK_KEY_r,      primary,       FIV_VIEW_COMMAND_RELOAD);
+	bind(bs, GDK_KEY_s,      primary,       FIV_VIEW_COMMAND_SAVE_PAGE);
 	bind(bs, GDK_KEY_s,      GDK_MOD1_MASK, FIV_VIEW_COMMAND_SAVE_FRAME);
 	bind(bs, GDK_KEY_Return, GDK_MOD1_MASK, FIV_VIEW_COMMAND_INFO);
 
@@ -1668,6 +1701,8 @@ fiv_view_command(FivView *self, FivViewCommand command)
 			G_OBJECT(self), view_properties[PROP_ENHANCE]);
 		swap_enhanced_image(self);
 
+	break; case FIV_VIEW_COMMAND_COPY:
+		copy(self);
 	break; case FIV_VIEW_COMMAND_PRINT:
 		print(self);
 	break; case FIV_VIEW_COMMAND_SAVE_PAGE:

fiv-view.h

@@ -50,6 +50,7 @@ typedef enum _FivViewCommand {
 	XX(FIV_VIEW_COMMAND_TOGGLE_FILTER,       "toggle-filter")                  \
 	XX(FIV_VIEW_COMMAND_TOGGLE_CHECKERBOARD, "toggle-checkerboard")            \
 	XX(FIV_VIEW_COMMAND_TOGGLE_ENHANCE,      "toggle-enhance")                 \
+	XX(FIV_VIEW_COMMAND_COPY,                "copy")                           \
 	XX(FIV_VIEW_COMMAND_PRINT,               "print")                          \
 	XX(FIV_VIEW_COMMAND_SAVE_PAGE,           "save-page")                      \
 	XX(FIV_VIEW_COMMAND_SAVE_FRAME,          "save-frame")                     \

fiv.c

@@ -82,23 +82,23 @@ struct key_section {
 static struct key help_keys_general[] = {
 	{"F1", "Show help"},
 	{"F10", "Open menu"},
-	{"<control>question", "Keyboard shortcuts"},
+	{"<Control>question", "Keyboard shortcuts"},
-	{"q <control>q", "Quit"},
+	{"q <Control>q", "Quit"},
-	{"<control>w", "Quit"},
+	{"<Control>w", "Quit"},
 	{}
 };
 
 static struct key help_keys_navigation[] = {
-	{"<control>l", "Open location..."},
+	{"<Control>l", "Open location..."},
-	{"<control>n", "Open a new window"},
+	{"<Control>n", "Open a new window"},
-	{"<alt>Left", "Go back in history"},
+	{"<Alt>Left", "Go back in history"},
-	{"<alt>Right", "Go forward in history"},
+	{"<Alt>Right", "Go forward in history"},
 	{}
 };
 
 static struct key help_keys_view[] = {
 	{"F11 f", "Toggle fullscreen"},
-	{"<alt><shift>d", "Toggle dark theme variant"},
+	{"<Alt><Shift>d", "Toggle dark theme variant"},
 	{}
 };
 
@@ -107,17 +107,17 @@ static struct key_group help_keys_browser[] = {
 	{"General: Navigation", help_keys_navigation},
 	{"General: View", help_keys_view},
 	{"Navigation", (struct key[]) {
-		{"<alt>Up", "Go to parent directory"},
+		{"<Alt>Up", "Go to parent directory"},
-		{"<alt>Home", "Go home"},
+		{"<Alt>Home", "Go home"},
 		{"Return", "Open selected item"},
 		{}
 	}},
 	{"View", (struct key[]) {
 		{"F9", "Toggle navigation sidebar"},
-		{"F5 r <control>r", "Reload"},
+		{"F5 r <Control>r", "Reload"},
-		{"h <control>h", "Toggle hiding unsupported files"},
+		{"h <Control>h", "Toggle hiding unsupported files"},
-		{"<control>plus", "Larger thumbnails"},
+		{"<Control>plus", "Larger thumbnails"},
-		{"<control>minus", "Smaller thumbnails"},
+		{"<Control>minus", "Smaller thumbnails"},
 		{}
 	}},
 	{}
@@ -135,14 +135,14 @@ static struct key_group help_keys_viewer[] = {
 	}},
 	{"View", (struct key[]) {
 		{"F8", "Toggle toolbar"},
-		{"F5 r <control>r", "Reload"},
+		{"F5 r <Primary>r", "Reload"},
 		{}
 	}},
 	{"Zoom", (struct key[]) {
-		{"<control>0", "Set zoom to 100%"},
+		{"<Primary>0", "Set zoom to 100%"},
 		{"1...9", "Set zoom to N:1"},
-		{"plus <control>plus", "Zoom in"},
+		{"plus <Primary>plus", "Zoom in"},
-		{"minus <control>minus", "Zoom out"},
+		{"minus <Primary>minus", "Zoom out"},
 		{"w", "Zoom to fit width if larger"},
 		{"h", "Zoom to fit height if larger"},
 		{}
@@ -175,10 +175,11 @@ static struct key_group help_keys_viewer[] = {
 		{}
 	}},
 	{"Tools", (struct key[]) {
-		{"<control>p", "Print..."},
+		{"<Primary>c", "Copy frame to clipboard"},
-		{"<control>s", "Save page as..."},
+		{"<Primary>p", "Print..."},
-		{"<control><shift>s", "Save frame as..."},
+		{"<Primary>s", "Save page as..."},
-		{"<alt>Return", "Show file information"},
+		{"<Primary><Shift>s", "Save frame as..."},
+		{"<Alt>Return", "Show file information"},
 		{}
 	}},
 	{}