Properly update the Pango contexts for the target surface

This fixes drawing on a surface that has different settings (like
scaling) than the display surface, by performing the measurements on a
layout properly set up for the target surface.

In practice, this fixes e.g. printing on a scaled surface.
---
 gtk/PlatGTK.cxx |    4 ++++
 1 file changed, 4 insertions(+)

1 files changed, 4 insertions, 0 deletions

diff --git a/gtk/PlatGTK.cxx b/gtk/PlatGTK.cxx
index 3aec7a6ab..beef9749d 100644
--- a/gtk/PlatGTK.cxx
+++ b/gtk/PlatGTK.cxx
@@ -553,6 +553,8 @@ void SurfaceImpl::Init(SurfaceID sid, WindowID wid) {
 	PLATFORM_ASSERT(wid);
 	context = cairo_reference(reinterpret_cast<cairo_t *>(sid));
 	pcontext = gtk_widget_create_pango_context(PWidget(wid));
+	// update the Pango context in case sid isn't the widget's surface
+	pango_cairo_update_context(context, pcontext);
 	layout = pango_layout_new(pcontext);
 	cairo_set_line_width(context, 1);
 	createdGC = true;
@@ -566,6 +568,8 @@ void SurfaceImpl::InitPixMap(int width, int height, Surface *surface_, WindowID
 	PLATFORM_ASSERT(wid);
 	context = cairo_reference(surfImpl->context);
 	pcontext = gtk_widget_create_pango_context(PWidget(wid));
+	// update the Pango context in case surface_ isn't the widget's surface
+	pango_cairo_update_context(context, pcontext);
 	PLATFORM_ASSERT(pcontext);
 	layout = pango_layout_new(pcontext);
 	PLATFORM_ASSERT(layout);