@cantoo/pdf-lib
Version:
Create and modify PDF files with JavaScript
59 lines • 2.03 kB
JavaScript
import { __awaiter } from "tslib";
import { PNG } from '../../utils/png.js';
/**
* A note of thanks to the developers of https://github.com/foliojs/pdfkit, as
* this class borrows from:
* https://github.com/devongovett/pdfkit/blob/e71edab0dd4657b5a767804ba86c94c58d01fbca/lib/image/png.coffee
*/
class PngEmbedder {
static for(imageData) {
return __awaiter(this, void 0, void 0, function* () {
const png = PNG.load(imageData);
return new PngEmbedder(png);
});
}
constructor(png) {
this.image = png;
this.bitsPerComponent = png.bitsPerComponent;
this.width = png.width;
this.height = png.height;
this.colorSpace = 'DeviceRGB';
}
embedIntoContext(context, ref) {
return __awaiter(this, void 0, void 0, function* () {
const SMask = this.embedAlphaChannel(context);
const xObject = context.flateStream(this.image.rgbChannel, {
Type: 'XObject',
Subtype: 'Image',
BitsPerComponent: this.image.bitsPerComponent,
Width: this.image.width,
Height: this.image.height,
ColorSpace: this.colorSpace,
SMask,
});
if (ref) {
context.assign(ref, xObject);
return ref;
}
else {
return context.register(xObject);
}
});
}
embedAlphaChannel(context) {
if (!this.image.alphaChannel)
return undefined;
const xObject = context.flateStream(this.image.alphaChannel, {
Type: 'XObject',
Subtype: 'Image',
Height: this.image.height,
Width: this.image.width,
BitsPerComponent: this.image.bitsPerComponent,
ColorSpace: 'DeviceGray',
Decode: [0, 1],
});
return context.register(xObject);
}
}
export default PngEmbedder;
//# sourceMappingURL=PngEmbedder.js.map