QGIS » QGIS Application

I can explain why this is happening, but don't have a solution for 0.8.

If an item is visible on the map, even just a small part of it, qgis draws the whole item. The svg writing part of Qt does the same, and uses a clip rectangle in svg to trim away the unwanted bits. From your example it looks like the large red shape is a single polygon, and a small part of that is included in the visible area.

It could be possible to use the existing trimming ability of qgis (originally there to work-around a problem X11 displays) to trim the svg output, but this would be a significant change that we wouldn't like to put in 0.8 - perhaps 0.9, hence I'll move this bug's milestone to 0.9

• blocker - bugs that should block the release. Since we are going to release pretty much 'come what may' I would like no bugs
• allocated to this category without consultation with me and / or PSC
• critical - bugs that cause the application to crash or corrupt data
• major - application features that do not function at all
• minor - features that function but imerfectly e.g. labels placing incorrectly
• trivial - gui useability issues or small issues with the documentation, install notes etc.

An update on this bug:

The svg implementation in Qt (v4.4.0 when I last checked) only supports the static features of SVG 1.2 Tiny. This doesn't include clipping of shapes, which is the subject of this ticket. There is a Qt bug filed for this (204966), but no indication of when it will be resolved.

Checked this in QGIS 1.0.0 Preview II. Confirmed this problem still exists.

The bus seems still open upstream. Could someone check with Qt 4.5? The QGIS version should have little relevance. Thanks.

Since version 1.1 qgis shows this message:

"The SVG export function in Qgis has several problems due to bugs and deficiencies in the Qt4 svg code. In particular, there are problems with layers not being clipped to the map bounding box. If you require a vector-based output file from Qgis it is suggested that you try printing to PostScript if the SVG output is not satisfactory."

Not a qgis issue. Closing?

Personally, I would suggest leaving it open. Although the problem stems from a Qt deficiency, it's possible to work around it with code in QGIS. I vaguely recall that there may have been code to do this which was removed in the port to Qt 4.

I'd also suggest leaving it open. It falls under the category of 'not our fault', but I think it's useful to have it flagged here, if only to remind us of the problem (and someone might fix it if it remains open in trac).

Ok, for me, pushing milestone to 1.2.0

Since the upstream bug (now located here) is marked as Won't Fix, it would seem that a workaround is the only remaining option.

Since the bug is marked as Won't Fix upstream, I disagree with the resolution being marked as upstream. This will need to be fixed in QGis because it's outside the scope of Qt.

This bug is still active: https://bugreports.qt-project.org/browse/QTBUG-23200

The issue linked in comment 17 appears to be a duplicate of the issue linked in comment 13. The latter is marked as Out of Scope, and the text of the former supports this.

From the bug report:

Deferred:

Fixing this bug would require implementing features of the SVG 1.1 Clip Module [1], and we currently only support SVG 1.2 Tiny.
A work-around is to use the viewBox property of the QSvgGenerator to set a clip manually (new in 4.5). While this will not clip individual paint operations it will clip the resulting document to a given rectangle.

[1] http://www.w3.org/TR/SVG11/masking.html#clip-mod

• https://bugreports.qt.io/browse/QTBUG-1865
• https://bugreports.qt.io/browse/QTBUG-23200