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author | Luboš Luňák <l.lunak@collabora.com> | 2020-05-22 21:13:14 +0200 |
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committer | Luboš Luňák <l.lunak@collabora.com> | 2020-06-22 13:31:20 +0200 |
commit | bb4b538ff6c2b10d41784819224171df07910eaf (patch) | |
tree | de56ae1cdc2fe15a05c288a363dfcc9a0446887d /vcl/skia/README | |
parent | 418e6c018ab28a8695519f803ae2c1937d97ada0 (diff) |
add debugging hints to Skia README
Change-Id: I32d9a8bf19cbff709c088c0e0a1d4830e877e88d
Diffstat (limited to 'vcl/skia/README')
-rw-r--r-- | vcl/skia/README | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/vcl/skia/README b/vcl/skia/README index f1248d90c3ea..c2077c5f0c25 100644 --- a/vcl/skia/README +++ b/vcl/skia/README @@ -18,6 +18,47 @@ Skia supports several methods to draw: There are more (OpenGL, Metal on Mac, etc.), but (as of now) they are not supported by VCL. +Logging: +======== + +Run LO with 'SAL_LOG=+INFO.vcl.skia' to get log information about Skia including +tracing each drawing operation. If you want log information without drawing operations, +use 'SAL_LOG=+INFO.vcl.skia-INFO.vcl.skia.trace'. + +Debugging: +========== + +Both SkiaSalBitmap and SkiaSalGraphicsImpl have a dump() method that writes a PNG +with the current contents. There is also SkiaHelper::dump() for dumping contents +of SkBitmap, SkImage and SkSurface. + +If there is a drawing problem, you can use something like the following piece of code +to dump an image after each relevant operation (or do it in postDraw() if you don't +know which operation is responsible). You can then find the relevant image +and match it with the responsible operation (run LO with 'SAL_LOG=+INFO.vcl.skia'). + + static int cnt = 0; + ++cnt; + char buf[100]; + sprintf(buf,"/tmp/a%05d.png", cnt); + SAL_DEBUG("CNT:" << cnt); + if(cnt > 4000) // skip some initial drawing operations + dump(buf); + + +Testing: +======== + +Currently unittests always use the 'headless' VCL backend. Use something like the following +to run VCL unittests with Skia (and possibly skip slowcheck): + +SAL_SKIA=raster SAL_ENABLESKIA=1 SAL_USE_VCLPLUGIN=gen make vcl.build vcl.unitcheck vcl.slowcheck + +You can also use 'visualbackendtest' to visually check some operations. Use something like: + +SAL_SKIA=raster SAL_ENABLESKIA=1 SAL_USE_VCLPLUGIN=gen [srcdir]/bin/run visualbackendtest + + GrContext sharing: ================== |