https://skia.org/docs/user/tips/

1，Use the scriptexperimental/tools/web_to_skp,ordo the following:

1. Launch Chrome or Chromium with--no-sandbox --enable-gpu-benchmarking
2. Open the JS console (Ctrl+Shift+J (Windows / Linux) or Cmd+Opt+J (MacOS))
3. Execute:chrome.gpuBenchmarking.printToSkPicture('/tmp')This returns “undefined” on success.

/tmp是個存放的目錄。windows可以寫成 chrome.gpuBenchmarking.printToSkPicture('d:\\mySkp')

Open the resulting file in theSkia Debugger, rasterize it withdm, or use Skia’sviewerto 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， 也可錄製多個頁面，還原成pdf

Capture a.mskpfile on a web page in Chromium

Multipage Skia Picture files capture the commands sent to produce PDFs and printed documents.

Use the scriptexperimental/tools/web_to_mskp,ordo the following:

1. Launch Chrome or Chromium with--no-sandbox --enable-gpu-benchmarking
2. Open the JS console (Ctrl+Shift+J (Windows / Linux) or Cmd+Opt+J (MacOS))
3. Execute:chrome.gpuBenchmarking.printPagesToSkPictures('/tmp/filename.mskp')This returns “undefined” on success.

Open the resulting file in theSkia Debuggeror process it withdm.

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

How to add hardware acceleration in Skia

There are two ways Skia takes advantage of specific hardware.

1. 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. Seesrc/opts/

Does Skia support Font hinting?

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 ofSkScalerContext. 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.

Does Skia shape text (kerning)?

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 useHarfBuzzto generate the glyphs and their positions, including kerning.

Here is an example of how to use Skia and HarfBuzz together. In the example, aSkTypefaceand ahb_face_tare created using the samemmap()ed.ttffont file. The HarfBuzz face is used to shape unicode text into a sequence of glyphs and positions, and theSkTypefacecan then be used to draw those glyphs.

How do I add drop shadow on text?

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);
}