[Qgis-developer] Problem with rendering when units are millimeters

[Marco Hugentobler]

Hi Alexander

Seems to be a problem with the python bindings. In C++, the render 
method is:
void QgsMapRenderer::render( QPainter* painter, double* forceWidthScale 
= 0 );

Somehow sip does not like that and forceWidthScale has a funny value 
(also, I cannot call the method with two arguments from python). If I 
change the function in qgsmaprenderer.sip to QgsMapRenderer::render( 
QPainter* painter ), forceWidthScale is 0 and it works.

Regards,
Marco

On 14.12.2012 15:51, Alexander Bruy wrote:
> Hi all,
>
> playing with map rendering I found strange issue: if layer style used
> "Millimeters" as unit type, this layers are displayed in QGIS but
> don't rendered when performing rendering to image from plugin/console.
>
> Here is minimal script to reproduce this. Add to canvas several
> line, point and polygon layers, ensure that style units are
> "Millimeters", zoom to some region. Then run script:
>
> from PyQt4.QtCore import *
> from PyQt4.QtGui import *
> canvas = qgis.utils.iface.mapCanvas()
> extent = canvas.extent()
> for l in canvas.layers():
>    layers.append(l.id())
> img = QImage(QSize(800, 600), QImage.Format_ARGB32_Premultiplied)
> color = QColor(255, 255, 255)
> img.fill(color.rgb())
> p = QPainter()
> p.begin(img)
> render = QgsMapRenderer()
> render.setLayerSet(layers)
> render.setExtent(extent)
> render.setOutputSize(img.size(), img.logicalDpiX())
> render.render(p)
> p.end()
> img.save("/tmp/render_issue.png","png")
>
> Output file will contain only polygonal layer(s), line and points are
> not rendered. But when style units changed to "Map units" all works
> fine. Same issue exists with labels.
>
> Any ideas what is wrong? Maybe I miss something obvious?
>
> Thanks


-- 
Dr. Marco Hugentobler
Sourcepole -  Linux & Open Source Solutions
Weberstrasse 5, CH-8004 Zürich, Switzerland
marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
Technical Advisor QGIS Project Steering Committee