https://skia.org/docs/user/tips/
1,Use the script experimental/tools/web_to_skp
, or do the following:
--no-sandbox --enable-gpu-benchmarking
chrome.gpuBenchmarking.printToSkPicture('/tmp')
This returns “undefined” on success./tmp是个存放的目录。windows可以写成 chrome.gpuBenchmarking.printToSkPicture('d:\\mySkp')
Open the resulting file in the Skia Debugger, rasterize it with dm
, or use Skia’s viewer
to view it:
out/Release/dm --src skp --skps /tmp/layer_0.skp -w /tmp \ --config 8888 gpu pdf --verbose ls -l /tmp/*/skp/layer_0.skp.* out/Release/viewer --skps /tmp --slide layer_0.skp
2, 也可录制多个页面,还原成pdf
.mskp
file on a web page in ChromiumMultipage Skia Picture files capture the commands sent to produce PDFs and printed documents.
Use the script experimental/tools/web_to_mskp
, or do the following:
--no-sandbox --enable-gpu-benchmarking
chrome.gpuBenchmarking.printPagesToSkPictures('/tmp/filename.mskp')
This returns “undefined” on success.Open the resulting file in the Skia Debugger or process it with dm
.
experimental/tools/mskp_parser.py /tmp/filename.mskp /tmp/filename.mskp.skp ls -l /tmp/filename.mskp.skp # open filename.mskp.skp in the debugger. out/Release/dm --src mskp --mskps /tmp/filename.mskp -w /tmp \ --config pdf --verbose ls -l /tmp/pdf/mskp/filename.mskp.pdf
There are two ways Skia takes advantage of specific hardware.
Custom bottleneck routines
There are sets of bottleneck routines inside the blits of Skia that can be replace on a platform in order to take advantage of specific CPU features. One such example is the NEON SIMD instructions on ARM v7 devices. See src/opts/
Skia has a built-in font cache, but it does not know how to actually render font files like TrueType into its cache. For that it relies on the platform to supply an instance of SkScalerContext
. This is Skia’s abstract interface for communicating with a font scaler engine. In src/ports you can see support files for FreeType, macOS, and Windows GDI font engines. Other font engines can easily be supported in a like manner.
Shaping is the process that translates a span of Unicode text into a span of positioned glyphs with the appropriate typefaces.
Skia does not shape text. Skia provides interfaces to draw glyphs, but does not implement a text shaper. Skia’s client’s often use HarfBuzz to generate the glyphs and their positions, including kerning.
Here is an example of how to use Skia and HarfBuzz together. In the example, a SkTypeface
and a hb_face_t
are created using the same mmap()
ed .ttf
font file. The HarfBuzz face is used to shape unicode text into a sequence of glyphs and positions, and the SkTypeface
can then be used to draw those glyphs.
void draw(SkCanvas* canvas) { const SkScalar sigma = 1.65f; const SkScalar xDrop = 2.0f; const SkScalar yDrop = 2.0f; const SkScalar x = 8.0f; const SkScalar y = 52.0f; const SkScalar textSize = 48.0f; const uint8_t blurAlpha = 127; auto blob = SkTextBlob::MakeFromString("Skia", SkFont(nullptr, textSize)); SkPaint paint; paint.setAntiAlias(true); SkPaint blur(paint); blur.setAlpha(blurAlpha); blur.setMaskFilter(SkMaskFilter::MakeBlur(kNormal_SkBlurStyle, sigma, 0)); canvas->drawColor(SK_ColorWHITE); canvas->drawTextBlob(blob.get(), x + xDrop, y + yDrop, blur); canvas->drawTextBlob(blob.get(), x, y, paint); }