Easy to Use API

Blend2D is written in C++ but it provides both C and C++ APIs. Public functionality is provided through C interface so that each feature of the library is accessible to both C and C++ users. The C API makes it possible to use Blend2D from many programming languages which are able to interface with C (either natively or through FFI). The primary goal of the C++ API is to make the library easy-to-use in C++ projects without the need of managing resources manually. It is built on top of the C API and turns all objects requiring initialization and finalization into smart objects that handle it in their constructors and destructors.

The snippets below provide an insight into the C and C++ APIs provided by Blend2D.

#include <blend2d.h>

// Each C API struct that requires a lifetime management
// ends with 'Core'. Such structs must be initialized by
// 'Init()' and finalized by 'Reset()' or by function
// that resets implicitly like 'blContextEnd()'.
void render(BLImageCore* img) {
  BLResult r;
  BLContextCore ctx;
  BLGradientCore gradient;

  r = blImageInitAs(img, 256, 256, BL_FORMAT_PRGB32);
  if (r != BL_SUCCESS) return;

  r = blContextInitAs(&ctx, img, NULL);
  if (r != BL_SUCCESS) return;

  BLLinearGradientValues values = { 0, 0, 256, 256 };
  blGradientInitAs(&gradient,
    BL_GRADIENT_TYPE_LINEAR, &values,
    BL_EXTEND_MODE_PAD, NULL, 0, NULL);

  blGradientAddStopRgba32(&gradient, 0.0, 0x00000000);
  blGradientAddStopRgba32(&gradient, 1.0, 0xFFFFFFFF);

  blContextSetCompOp(&ctx, BL_COMP_OP_SRC_COPY);
  blContextSetFillStyle(&ctx, &gradient);

  blContextFillAll(&ctx);
  blContextEnd(&ctx);

  // Manual cleanup is necessary in C.
  blGradientDestroy(&gradient);
}

#include <blend2d.h>

// C++ API is automatically provided in C++ mode. Each
// 'Core' struct has also its C++ counterpart that
// doesn't have the suffix (BLImageCore -> BLImage)
// and provides scope-bound resource management.
void render(BLImage& img) noexcept {
  BLResult r;
  BLContext ctx;
  BLGradient gradient;

  r = img.create(256, 256, BL_FORMAT_PRGB32);
  if (r != BL_SUCCESS) return;

  r = ctx.begin(img);
  if (r != BL_SUCCESS) return;

  // There are many overloads available in C++ API.
  gradient.create(
    BLLinearGradientValues(0, 0, 256, 256),
    BL_EXTEND_MODE_PAD);

  gradient.addStop(0.0, BLRgba32(0x00000000));
  gradient.addStop(1.0, BLRgba32(0xFFFFFFFF));

  ctx.setCompOp(BL_COMP_OP_SRC_COPY);
  ctx.setFillStyle(gradient);

  ctx.fillAll();
  ctx.end();

  // C++ smart objects take care of cleanup
  // automatically when they go out of scope.
}

Please note that both examples were written to be line-by-line comparable and to not use excessive error handling. More C++ examples and their corresponding outputs can be seen on Getting Started page.

Composition & Blending

Blend2D supports all Porter & Duff compositing operators and a wide range of blend modes defined by SVG, CSS, and PDF specifications. Composition and blending modes can be applied to any rendering operation including fills, strokes, and image blits.

Beta Version

Blend2D is currently in a beta testing mode, which means that you can download and use the library, but a certain functionality may be limited or not working as expected. Project roadmap can be tracked via Roadmap page and Issues page on GitHub. We are interested in your feedback! So give it a try, download Blend2D, play with it, and let us know what should be improved.