After more investigation I've discovered that the different extents (and line counts) are caused by the scaling matrix set in cairo context used for rendering. To summarize: Layouts with the same text, same attributes and same width may have the lines wrapping in a non consistent manner if the scaling matrix changes (most usually the line count changes by +1/-1) Is this behavior intended or this could be a bug? This seems pretty weird to me, as scaling down the visualized text should make characters smaller, but should not cause layout changes Regards, Alessandro On Friday 01 April 2011 16:29:04 Alessandro Pignotti wrote: > Hi everyone, > > I'm experimenting with using Pango to determine the size of a layout before > knowing the actual surface where it will be drawn on. > > I'm noticing that the extends returned by pango_layout_get_extents for a > temporary layout and the layout created by pango_cairo_create_layout at > render time are not consistent. For both layouts the width and attributes > are set at the same values. > > Are there any guidelines to guarantee consistent layout results? Could the > problem be related to subpixel hinting that is configured at system (GTK) > level? Is there any way to verify that the same font is actually being > selected in the two case I described? > > Thanks a lot for your help, please let me know if more information is > needed Alessandro Pignotti
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