[cairo] Flickering on some scaling-values
andreas.wittmann at wittnet.org
Thu Aug 21 02:44:11 PDT 2014
I'm new to cairo so this is maybe a simple question but i haven't found
any answers using the internet. I'm using Linux/Debian and the newest
cairo-release 1.12.16 (But my/this problem will also occur on previous
wxWidgets is also used, i'm using a simple render-function which looks
like this and which is called from the wxWidgets-framework:
void BasicDrawPane::render(wxDC& dc2)
cairo_t* cairo_image = gdk_cairo_create((GdkWindow*)dc.GetHandle());
cairo_t *cr = cairo_image;
cairo_scale(cr, global_scale_x, global_scale_y);
cairo_translate(cr, 0.5, 0.5);
cairo_rectangle(cr, 0.0, 0.0, rect.width / global_scale_x,
rect.height / global_scale_y);
cairo_set_source_rgb(cr, 255, 255, 255);
// drawing some shapes ...
The shapes will be drawn (eg. from a mouse-event) without any flickering
if the global-scales (global_scale_x, global_scale_y) are NOT 2.0, 4.0,
6.0, 8.0, 10.0, ... and so on. A value of eg. 2.1 would work without any
Could anybody please give me some direction on how to solve this problem
or why it happens?
The translation is used for drawing thin lines.
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