private void resizeXfirst()

in src/main/java/org/apache/pdfbox/jbig2/image/Resizer.java [201:274]
47 lines of code
8 McCabe index (conditional complexity)

    private void resizeXfirst(final Object src, final Rectangle srcBounds, final Object dst,
            final Rectangle dstBounds, final ParameterizedFilter xFilter,
            final ParameterizedFilter yFilter)
    {
        // source scanline buffer
        final Scanline buffer = createScanline(src, dst, srcBounds.width);

        // accumulator buffer
        final Scanline accumulator = createScanline(src, dst, dstBounds.width);

        // a sampled filter for source pixels for each dest x position
        final Weighttab xWeights[] = createXWeights(srcBounds, dstBounds, xFilter);

        // Circular buffer of active lines
        final int yBufferSize = yFilter.width + 2;
        final Scanline lineBuffer[] = new Scanline[yBufferSize];
        for (int y = 0; y < yBufferSize; y++)
        {
            lineBuffer[y] = createScanline(src, dst, dstBounds.width);
            lineBuffer[y].y = -1; /* mark scanline as unread */
        }

        // range of source and destination scanlines in regions
        final int srcY0 = srcBounds.y;
        final int srcY1 = srcBounds.y + srcBounds.height;
        final int dstY0 = dstBounds.y;
        final int dstY1 = dstBounds.y + dstBounds.height;

        int yFetched = -1; // used to assert no backtracking

        // loop over dest scanlines
        for (int dstY = dstY0; dstY < dstY1; dstY++)
        {
            // a sampled filter for source pixels for each dest x position
            final Weighttab yWeight = new Weighttab(yFilter, weightOne,
                    mappingY.mapPixelCenter(dstY), srcY0, srcY1 - 1, true);

            accumulator.clear();

            // loop over source scanlines that contribute to this dest scanline
            for (int srcY = yWeight.i0; srcY <= yWeight.i1; srcY++)
            {
                final Scanline srcBuffer = lineBuffer[srcY % yBufferSize];

                if (debug)
                    System.out.println("  abuf.y / ayf " + srcBuffer.y + " / " + srcY);

                if (srcBuffer.y != srcY)
                {
                    // scanline needs to be fetched from src raster
                    srcBuffer.y = srcY;

                    if (srcY0 + srcY <= yFetched)
                        throw new AssertionError(
                                "Backtracking from line " + yFetched + " to " + (srcY0 + srcY));

                    buffer.fetch(srcBounds.x, srcY0 + srcY);

                    yFetched = srcY0 + srcY;

                    // filter it into the appropriate line of linebuf (xfilt)
                    buffer.filter(NO_SHIFT, bitsPerChannel, xWeights, srcBuffer);
                }

                // add weighted tbuf into accum (these do yfilt)
                srcBuffer.accumulate(yWeight.weights[srcY - yWeight.i0], accumulator);
            }

            accumulator.shift(finalShift);
            accumulator.store(dstBounds.x, dstY);
            if (debug)
                System.out.printf("\n");
        }
    }