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Assertion fails in BufferPainter::TransformOp() with rotated text [message #47288]

Tue, 03 January 2017 09:55

Tom1
Messages: 1212
Registered: March 2007

Senior Contributor

Hi,

When calling Painter::DrawText (for rotated text output):

	...
	painter.DrawText(x,y,rotation,text,font,Black());
	...

The following assertion triggers in DEBUG mode:

void   BufferPainter::TransformOp(const Xform2D& m)
{
	ASSERT_(IsNull(current), "Cannot change transformation during path definition");
	pathattr.mtx = attr.mtx = m * attr.mtx;
}

In RELEASE mode DrawText works just as it should, allowing rotation of text about its insertion point while retaining original transformation in the background (because of Begin()/End() pair involved). Similar temporary transformations are needed when rendering constant blocks of vector graphics at different locations with different scaling and rotation attributes. I guess Begin()/End() pairs should be used there too to preserve original transformation.

Is this assertion really needed for something?

Best regards,

Tom

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