When recreating the canvas, do a full redraw so that all the dialogs

behind the credits show. Until we have a new canvas, don't draw any credits
text, or it too will show up on the canvas.

The latter, at the very least, was a bug in my original patch.

svn-id: r17621

2 files changed, 12 insertions, 2 deletions

diff --git a/gui/about.cpp b/gui/about.cpp
index d23ce9c0a4..a659392194 100644
--- a/gui/about.cpp
+++ b/gui/about.cpp
@@ -121,6 +121,7 @@ void AboutDialog::open() {
 	_modifiers = 0;
 	_willClose = false;
 	_canvas.pixels = NULL;
+	_screenHasChanged = false;
 
 	Dialog::open();
 }
@@ -138,6 +139,7 @@ void AboutDialog::drawDialog() {
 		// static background for the remainder of the credits.
 		g_gui.blendRect(_x, _y, _w, _h, g_gui._bgcolor);
 		g_gui.copyToSurface(&_canvas, _x, _y, _w, _h);
+		_screenHasChanged = false;
 	}
 
 	g_gui.drawSurface(_canvas, _x, _y);
@@ -212,6 +214,11 @@ void AboutDialog::drawDialog() {
 
 
 void AboutDialog::handleTickle() {
+	// We're in the process of doing a full redraw. This will be used as
+	// background for the text, so we don't want any text on it.
+	if (_screenHasChanged)
+		return;
+
 	const uint32 t = getMillis();
 	int scrollOffset = ((int)t - (int)_scrollTime) / kScrollMillisPerPixel;
 	if (scrollOffset > 0) {
@@ -235,10 +242,12 @@ void AboutDialog::handleTickle() {
 }
 
 void AboutDialog::handleScreenChanged() {
-	// The screen has changed. Reset the canvas, to ensure it gets
-	// refreshed next time a redraw takes place.
+	// The screen has changed. Reset the canvas, and issue a full redraw.
+	// Until we have a new canvas, don't draw any credits text.
 	free(_canvas.pixels);
 	_canvas.pixels = NULL;
+	_screenHasChanged = true;
+	draw();
 }
 
 void AboutDialog::handleMouseUp(int x, int y, int button, int clickCount) {
diff --git a/gui/about.h b/gui/about.h
index 65dbb49f40..89cb61df22 100644
--- a/gui/about.h
+++ b/gui/about.h
@@ -37,6 +37,7 @@ protected:
 	byte		_modifiers;
 	bool		_willClose;
 	Graphics::Surface	_canvas;
+	bool		_screenHasChanged;
 
 public:
 	AboutDialog();