tom-weatherhead/thaw-image-processing.ts

// thaw-image-processing.ts/src/map-coordinates.ts

/* eslint-disable no-fallthrough */

import { ThAWImageBufferType } from './image';

export type CoordinatesMapperType = (
    dstBuffer: ThAWImageBufferType,
    dstWidth: number,
    dstHeight: number,
    dstInitialRowOffset: number,
    dstRowStride: number,
    dstPixelStride: number,
    srcBuffer: ThAWImageBufferType,
    srcInitialRowOffset: number,
    srcRowStride: number,
    srcPixelStride: number,
    numBytesPerPixel: number
) => void;

export function mapImageByCoordinatesFromBuffer(
    dstBuffer: ThAWImageBufferType,
    dstWidth: number,
    dstHeight: number,
    dstInitialRowOffset: number,
    dstRowStride: number,
    dstPixelStride: number,
    srcBuffer: ThAWImageBufferType,
    srcInitialRowOffset: number,
    srcRowStride: number,
    srcPixelStride: number,
    numBytesPerPixel: number
): void {
    let dstRowOffset = dstInitialRowOffset;
    let srcRowOffset = srcInitialRowOffset;

    for (let row = 0; row < dstHeight; row++) {
        let dstPixelOffset = dstRowOffset;
        let srcPixelOffset = srcRowOffset;

        for (let col = 0; col < dstWidth; col++) {
            switch (numBytesPerPixel) {
                case 4:
                    dstBuffer[dstPixelOffset + 3] =
                        srcBuffer[srcPixelOffset + 3];
                case 3: // eslint-disable-line
                    dstBuffer[dstPixelOffset + 2] =
                        srcBuffer[srcPixelOffset + 2];
                    dstBuffer[dstPixelOffset + 1] =
                        srcBuffer[srcPixelOffset + 1];
                case 1: // eslint-disable-line
                    dstBuffer[dstPixelOffset + 0] =
                        srcBuffer[srcPixelOffset + 0];
                default:
                    // eslint-disable-line
                    break;
            }

            dstPixelOffset += dstPixelStride;
            srcPixelOffset += srcPixelStride;
        }

        dstRowOffset += dstRowStride;
        srcRowOffset += srcRowStride;
    }
}