diff options
Diffstat (limited to 'area_unix.go')
| -rw-r--r-- | area_unix.go | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/area_unix.go b/area_unix.go index 83aafc5..8f9fc8f 100644 --- a/area_unix.go +++ b/area_unix.go @@ -45,11 +45,18 @@ func gtkAreaGetControl(scrollarea *gtkWidget) *gtkWidget { //export our_area_draw_callback func our_area_draw_callback(widget *C.GtkWidget, cr *C.cairo_t, data C.gpointer) C.gboolean { var x, y, w, h C.double + var maxwid, maxht C.gint s := (*sysData)(unsafe.Pointer(data)) // thanks to desrt in irc.gimp.net/#gtk+ C.cairo_clip_extents(cr, &x, &y, &w, &h) cliprect := image.Rect(int(x), int(y), int(w), int(h)) + // the cliprect can actually fall outside the size of the Area; clip it by intersecting the two rectangles + C.gtk_widget_get_size_request(widget, &maxwid, &maxht) + cliprect = image.Rect(0, 0, int(maxwid), int(maxht)).Intersect(cliprect) + if cliprect.Empty() { // no intersection; nothing to paint + return C.FALSE // signals handled without stopping the event chain (thanks to desrt again) + } i := s.handler.Paint(cliprect) // pixel order is [R G B A] (see Example 1 on https://developer.gnome.org/gdk-pixbuf/2.26/gdk-pixbuf-The-GdkPixbuf-Structure.html) so we don't have to convert anything // gdk-pixbuf is not alpha-premultiplied (thanks to desrt in irc.gimp.net/#gtk+) |