tom-weatherhead/thaw-image-processing.ts

// thaw-image-processing.ts/src/rotate.ts

import { mapImageByCoordinatesFromBuffer } from '../util/map-coordinates';
import { createThAWImage, IThAWImage } from '../util/image';

export function rotate90DegreesClockwiseFromImage(
    srcImage: IThAWImage
): IThAWImage {
    const dstImage = createThAWImage(
        srcImage.height,
        srcImage.width,
        srcImage.bytesPerPixel
    );

    mapImageByCoordinatesFromBuffer(
        dstImage.data,
        dstImage.width,
        dstImage.height,
        0,
        dstImage.bytesPerLine,
        dstImage.bytesPerPixel,
        srcImage.data,
        (srcImage.height - 1) * srcImage.bytesPerLine,
        srcImage.bytesPerPixel,
        -srcImage.bytesPerLine,
        srcImage.bytesPerPixel
    );

    return dstImage;
}

export function rotate90DegreesCounterclockwiseFromImage(
    srcImage: IThAWImage
): IThAWImage {
    const dstImage = createThAWImage(
        srcImage.height,
        srcImage.width,
        srcImage.bytesPerPixel
    );

    mapImageByCoordinatesFromBuffer(
        dstImage.data,
        dstImage.width,
        dstImage.height,
        0,
        dstImage.bytesPerLine,
        dstImage.bytesPerPixel,
        srcImage.data,
        (srcImage.width - 1) * srcImage.bytesPerPixel,
        -srcImage.bytesPerPixel,
        srcImage.bytesPerLine,
        srcImage.bytesPerPixel
    );

    return dstImage;
}

export function rotate180DegreesFromImage(srcImage: IThAWImage): IThAWImage {
    const dstImage = createThAWImage(
        srcImage.width,
        srcImage.height,
        srcImage.bytesPerPixel
    );

    mapImageByCoordinatesFromBuffer(
        dstImage.data,
        dstImage.width,
        dstImage.height,
        0,
        dstImage.bytesPerLine,
        dstImage.bytesPerPixel,
        srcImage.data,
        (srcImage.height - 1) * srcImage.bytesPerLine +
            (srcImage.width - 1) * srcImage.bytesPerPixel,
        -srcImage.bytesPerLine,
        -srcImage.bytesPerPixel,
        srcImage.bytesPerPixel
    );

    return dstImage;
}