1 files changed, 98 insertions, 0 deletions
diff --git a/src/display/canvas-debug.cpp b/src/display/canvas-debug.cpp
new file mode 100644
index 0000000..03db61f
--- /dev/null
+++ b/src/display/canvas-debug.cpp
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * A simple surface for debugging the canvas. Shows how tiles are drawn.
+ *
+ * Author:
+ *   Tavmjong Bah <tavmjong@free.fr>
+ *
+ * Copyright (C) 2017 Tavmjong Bah
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "canvas-debug.h"
+#include "sp-canvas.h"
+#include "cairo-utils.h"
+#include "ui/event-debug.h"
+
+namespace {
+
+static void   sp_canvas_debug_destroy(SPCanvasItem *item);
+static void   sp_canvas_debug_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
+static void   sp_canvas_debug_render (SPCanvasItem *item, SPCanvasBuf *buf);
+static int    sp_canvas_debug_event  (SPCanvasItem *item, GdkEvent *event);
+
+} // namespace
+
+G_DEFINE_TYPE(SPCanvasDebug, sp_canvas_debug, SP_TYPE_CANVAS_ITEM);
+
+static void sp_canvas_debug_class_init (SPCanvasDebugClass *klass)
+{
+    klass->destroy = sp_canvas_debug_destroy;
+    klass->update  = sp_canvas_debug_update;
+    klass->render  = sp_canvas_debug_render;
+    klass->event   = sp_canvas_debug_event;
+}
+
+static void sp_canvas_debug_init (SPCanvasDebug *debug)
+{
+    debug->pickable = true; // So we can receive events.
+}
+
+namespace {
+static void sp_canvas_debug_destroy (SPCanvasItem *object)
+{
+    g_return_if_fail (object != nullptr);
+    g_return_if_fail (SP_IS_CANVAS_DEBUG (object));
+
+    if (SP_CANVAS_ITEM_CLASS(sp_canvas_debug_parent_class)->destroy) {
+        SP_CANVAS_ITEM_CLASS(sp_canvas_debug_parent_class)->destroy(object);
+    }
+}
+
+static void sp_canvas_debug_update( SPCanvasItem *item, Geom::Affine const &/*affine*/, unsigned int /*flags*/ )
+{
+    // We cover the entire canvas
+    item->x1 = -G_MAXINT;
+    item->y1 = -G_MAXINT;
+    item->x2 = G_MAXINT;
+    item->y2 = G_MAXINT;
+}
+
+static void sp_canvas_debug_render( SPCanvasItem *item, SPCanvasBuf *buf)
+{
+    if (!buf->ct) {
+        return;
+    }
+
+    cairo_set_line_width (buf->ct, 2);
+
+    // Draw box around buffer (for debugging)
+    cairo_new_path (buf->ct);
+    cairo_move_to (buf->ct, 0, 0);
+    cairo_line_to (buf->ct, buf->rect.width(), 0);
+    cairo_line_to (buf->ct, buf->rect.width(), buf->rect.height());
+    cairo_line_to (buf->ct,                 0, buf->rect.height());
+    cairo_close_path (buf->ct);
+    ink_cairo_set_source_rgba32 (buf->ct, 0xff7f7f7f);
+    cairo_stroke (buf->ct);
+}
+
+static int sp_canvas_debug_event  (SPCanvasItem *item, GdkEvent *event)
+{
+    ui_dump_event (event, Glib::ustring("sp_canvas_debug_event"));
+    return false; // We don't use any events...
+}
+
+} // namespace
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :