function setGlobalCompositeOperation(newGlobalCompositeOperation) {
var vgBlendMode = compositeOperation2vg[newGlobalCompositeOperation];
if (vgBlendMode) {
globalCompositeOperation = newGlobalCompositeOperation;
blendMode = vgBlendMode;
vg.setI(vg.VGParamType.VG_BLEND_MODE, vgBlendMode);
} // TODO else ? (@see spec)
var saveBlendMode = vg.getI(vg.VGParamType.VG_BLEND_MODE);
}
function dropShadow(paintFn) {
var success;
var saveBlendMode = vg.getI(vg.VGParamType.VG_BLEND_MODE);
vg.getMatrix(shadowTransform);
success = vg.egl.makeCurrent(shadowSurface, shadowContext);
vg.loadMatrix(shadowTransform);
vg.clear(0, 0, width, height);
vg.translate(shadowOffsetX, shadowOffsetY);
paintFn();
vg.translate(-shadowOffsetX, -shadowOffsetY);
vg.setI(vg.VGParamType.VG_BLEND_MODE, vg.VGBlendMode.VG_BLEND_SRC_IN);
vg.setParameterI(shadowPaint, vg.VGPaintParamType.VG_PAINT_TYPE,
vg.VGPaintType.VG_PAINT_TYPE_COLOR);
vg.setParameterFV(shadowPaint, vg.VGPaintParamType.VG_PAINT_COLOR,
shadowColor);
vg.setPaint(shadowPaint, vg.VGPaintMode.VG_FILL_PATH);
vg.getMatrix(shadowTransform);
vg.loadIdentity();
var vgPath = vg.createPath(vg.VG_PATH_FORMAT_STANDARD,
vg.VGPathDatatype.VG_PATH_DATATYPE_F,
1.0 /* scale */ , 0.0 /* bias */,
5 /* segCapacityHint */,
5 /* coordCapacityHint */,
vg.VGPathCapabilities.VG_PATH_CAPABILITY_APPEND_TO);
vg.vgu.rect(vgPath, 0, 0, width, height);
vg.drawPath(vgPath, vg.VGPaintMode.VG_FILL_PATH);
vg.destroyPath(vgPath);
vg.loadMatrix(shadowTransform);
vg.setI(vg.VGParamType.VG_BLEND_MODE, vg.VGBlendMode.VG_BLEND_SRC_OVER);
if (shadowBlur !== 0) {
var sigma = shadowBlur / 2;
vg.gaussianBlur(shadowDstImage, shadowSrcImage,
sigma, sigma,
vg.VGTilingMode.VG_TILE_PAD);
}
success = vg.egl.makeCurrent(vg.screen.surface, vg.screen.context);
vg.setI(vg.VGParamType.VG_BLEND_MODE, vg.VGBlendMode.VG_BLEND_SRC_OVER);
vg.getMatrix(shadowTransform);
vg.loadIdentity();
vg.drawImage(shadowBlur !== 0 ? shadowDstImage : shadowSrcImage);
vg.loadMatrix(shadowTransform);
vg.setI(vg.VGParamType.VG_BLEND_MODE, saveBlendMode);
}