[jira] [Resolved] (FOP-2297) Degraded output from SVG external graphic on upgrade from fop-1.0 to fop-1.1

["Vincent Hennebert (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FOP-2297?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vincent Hennebert resolved FOP-2297.
------------------------------------

    Resolution: Not a Problem

AFAICT, the code is working as expected. In fact, before the change from rev. 987423 there were two bugs:
* the target-resolution was having an effect on the image size, while it shouldn't (this is source-resolution's purpose);
* the target-resolution was not being taken into account when generating raster images to represent constructs like filter effects.

That means that raster images were being generated according to the SVG's original size rather than the target resolution.

If the SVG ended up being scaled down in the FO document, the result was fine since the raster image was also scaled down. However, if the SVG had to be scaled up, the pixellisation was showing up. This is what prompted the change from rev. 987423.

The consequence of that change is that, with default settings, images from scaled-down SVGs are now generated at a lower resolution (smaller number of pixels) than before. Which may make them look more pixellated, like for the attached Google.svg image.

The good news is that it is now possible to control the resolution of raster images generated from SVG, thanks to the target-resolution config parameter being effective. The default value of 72dpi is probably a bit low for a printed output, and it wouldn't be unreasonable to set it at 300dpi.

The current behaviour is better than before since the size of raster images can now be controlled, potentially saving a lot of memory and CPU if the SVG's original size is huge.

> Degraded output from SVG external graphic on upgrade from fop-1.0 to fop-1.1
> ----------------------------------------------------------------------------
>
>                 Key: FOP-2297
>                 URL: https://issues.apache.org/jira/browse/FOP-2297
>             Project: Fop
>          Issue Type: Bug
>          Components: renderer/svg
>    Affects Versions: 1.1, trunk
>         Environment: Verified on both MacOSX and Win32.
>            Reporter: Glenn Adams
>         Attachments: Google.svg, svg-flattening-1.0.pdf, svg-flattening-1.1.pdf, svg-flattening.fo, test.bad.pdf, test.fo.xml, test.good.pdf, test987422.pdf, test987423.pdf
>
>
> When updating from JDK 1.7.0_21 to 1.7.0_25, PDF output of SVG external graphics appears to switch to low resolution, poor rendering quality.



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