Function avifDecoderDataCopyTileToImage

src/read.c:1823–1878

Copies over the pixels from the tile into dstImage. Verifies that the relevant properties of the tile match those of the first tile in case of a grid.

// Copies over the pixels from the tile into dstImage.
// Verifies that the relevant properties of the tile match those of the first tile in case of a grid.
static avifResult avifDecoderDataCopyTileToImage(avifDecoderData * data,
                                                 const avifTileInfo * info,
                                                 avifImage * dstImage,
                                                 const avifTile * tile,
                                                 unsigned int tileIndex)
{
    const avifTile * firstTile = &data->tiles.tile[info->firstTileIndex];
    if (tile != firstTile) {
        // Check for tile consistency. All tiles in a grid image should match the first tile in the properties checked below.
        if ((tile->image->width != firstTile->image->width) || (tile->image->height != firstTile->image->height) ||
            (tile->image->depth != firstTile->image->depth) || (tile->image->yuvFormat != firstTile->image->yuvFormat) ||
            (tile->image->yuvRange != firstTile->image->yuvRange) || (tile->image->colorPrimaries != firstTile->image->colorPrimaries) ||
            (tile->image->transferCharacteristics != firstTile->image->transferCharacteristics) ||
            (tile->image->matrixCoefficients != firstTile->image->matrixCoefficients)) {
            avifDiagnosticsPrintf(data->diag, "Grid image contains mismatched tiles");
            return AVIF_RESULT_INVALID_IMAGE_GRID;
        }
    }

    // Only keep the relevant planes in the destination image. Otherwise,
    // unjustified failures may come from trying to copy alpha tiles with odd
    // coordinates into the dstImage when the chroma planes are subsampled.
    avifImage dstView;
    avifImageSetDefaults(&dstView);
    const avifCropRect srcViewRect = { 0, 0, dstImage->width, dstImage->height };
    AVIF_ASSERT_OR_RETURN(avifImageSetViewRect(&dstView, dstImage, &srcViewRect) == AVIF_RESULT_OK);
    if (avifIsAlpha(tile->input->itemCategory)) {
        avifImageFreePlanes(&dstView, AVIF_PLANES_YUV);
        dstView.yuvFormat = AVIF_PIXEL_FORMAT_NONE;
    } else {
        avifImageFreePlanes(&dstView, AVIF_PLANES_A);
    }

    avifImage srcTileView;
    avifImageSetDefaults(&srcTileView);
    avifImage dstTileView;
    avifImageSetDefaults(&dstTileView);
    avifCropRect dstTileViewRect = { 0, 0, firstTile->image->width, firstTile->image->height };
    if (info->grid.rows > 0 && info->grid.columns > 0) {
        unsigned int rowIndex = tileIndex / info->grid.columns;
        unsigned int colIndex = tileIndex % info->grid.columns;
        dstTileViewRect.x = firstTile->image->width * colIndex;
        dstTileViewRect.y = firstTile->image->height * rowIndex;
        if (dstTileViewRect.x + dstTileViewRect.width > info->grid.outputWidth) {
            dstTileViewRect.width = info->grid.outputWidth - dstTileViewRect.x;
        }
        if (dstTileViewRect.y + dstTileViewRect.height > info->grid.outputHeight) {
            dstTileViewRect.height = info->grid.outputHeight - dstTileViewRect.y;
        }
    }
    const avifCropRect srcTileViewRect = { 0, 0, dstTileViewRect.width, dstTileViewRect.height };
    AVIF_ASSERT_OR_RETURN(avifImageSetViewRect(&dstTileView, &dstView, &dstTileViewRect) == AVIF_RESULT_OK);
    AVIF_ASSERT_OR_RETURN(avifImageSetViewRect(&srcTileView, tile->image, &srcTileViewRect) == AVIF_RESULT_OK);
    avifImageCopySamples(&dstTileView, &srcTileView, avifIsAlpha(tile->input->itemCategory) ? AVIF_PLANES_A : AVIF_PLANES_YUV);
    return AVIF_RESULT_OK;
}

// If colorId == 0 (a sentinel value as item IDs must be nonzero), accept any found EXIF/XMP metadata. Passing in 0