“编译”Skia

国内不适合自己编译。Github 有不止一个自动构建的SKIA二进制build，涵盖多个操作系统，可直接取而用之。

推荐大名鼎鼎的JetBrains维护的仓库，地址是 https://github.com/JetBrains/skia-build。含静态库与头文件。release静态库解压出来180MB，debug解压出来一两个G。推荐直接用release版本的。

绘制中文字符串

直接用Skia的SkString就可以，无需多次转换。如果显示方框，那说明字体不对，要设置宋体。

auto pFace = SkTypeface::MakeFromName("宋体", SkFontStyle::Normal());
SkFont font;
font.setTypeface(pFace);SkString string("加载图片 #");canvas->drawString(string, 1, 28, font, textpaint);

完整代码见文末的demo

加载并显示PNG图片等

百度“Skia绘制图片”出来的结果大多已经过时。

最新方法，要用 SkCodec::MakeFromData 解析二进制流，得到SkCodec 与 SkImageInfo，中SkImageInfo包括图片尺寸信息，然后再解码为 SkBitmap。

    DWORD fileLength;char* memFile;... 加载文件到 memFile数组中sk_sp<SkData> data = SkData::MakeWithoutCopy(memFile, fileLength);auto codec = SkCodec::MakeFromData(data);if (!codec) {LogIs(2, "FAILED DECODING FILE!");}SkImageInfo codecInfo = codec->getInfo();auto alphaType = codecInfo.isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType;auto decodeInfo = SkImageInfo::Make(codecInfo.width(), codecInfo.height(), kN32_SkColorType, alphaType);SkBitmap* skBitmap = new SkBitmap();char* pixels = new char[codecInfo.width()*codecInfo.height()*32];skBitmap->setInfo(decodeInfo, codecInfo.width()*32);skBitmap->setPixels(pixels);auto decodeResult = codec->getPixels(decodeInfo, pixels, codecInfo.width()*32);

decodeResult 等于零代表成功，其他可能的数值：

    /***  Error codes for various SkCodec methods.*/enum Result {/***  General return value for success.*/kSuccess, 0/***  The input is incomplete. A partial image was generated.*/kIncompleteInput, 1/***  Like kIncompleteInput, except the input had an error.**  If returned from an incremental decode, decoding cannot continue,*  even with more data.*/kErrorInInput, 2/***  The generator cannot convert to match the request, ignoring*  dimensions.*/kInvalidConversion, 3/***  The generator cannot scale to requested size.*/kInvalidScale, 4/***  Parameters (besides info) are invalid. e.g. NULL pixels, rowBytes*  too small, etc.*/kInvalidParameters, 5/***  The input did not contain a valid image.*/kInvalidInput, 6/***  Fulfilling this request requires rewinding the input, which is not*  supported for this input.*/kCouldNotRewind, 7/***  An internal error, such as OOM.*/kInternalError, 8/***  This method is not implemented by this codec.*  FIXME: Perhaps this should be kUnsupported?*/kUnimplemented, 9};