From 299e27838df58153e76e5b3d9bee46dc2a867dec Mon Sep 17 00:00:00 2001 From: Michael Dominic K Date: Wed, 8 Dec 2010 13:44:03 +0100 Subject: Use a different dither distribution matrix + a bit of rand. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Also don't dither on edges. Improves dithering over tiles/scaled smooth gradients. Merge-request: 971 Reviewed-by: Samuel Rødal --- src/plugins/graphicssystems/meego/dithering.cpp | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/src/plugins/graphicssystems/meego/dithering.cpp b/src/plugins/graphicssystems/meego/dithering.cpp index 1a2e3fa..ca303a8 100644 --- a/src/plugins/graphicssystems/meego/dithering.cpp +++ b/src/plugins/graphicssystems/meego/dithering.cpp @@ -154,7 +154,10 @@ unsigned short* convertRGB32_to_RGB565(const unsigned char *in, int width, int h // Add the diffusion for this pixel we stored in the accumulator. // >> 7 because the values in accumulator are stored * 128 - component[c] += accumulator[c][x] >> 7; + if (x != 0 && x != (width - 1)) { + if (accumulator[c][x] >> 7 != 0) + component[c] += rand() % accumulator[c][x] >> 7; + } // Make sure we're not over the boundaries. CLAMP_256(component[c]); @@ -172,10 +175,10 @@ unsigned short* convertRGB32_to_RGB565(const unsigned char *in, int width, int h // Distribute the difference according to the matrix in the // accumulation bufffer. - ACCUMULATE(accumulator[c], x + 1, 0, width, diff * 7); - ACCUMULATE(accumulator[c], x - 1, 1, width, diff * 3); + ACCUMULATE(accumulator[c], x + 1, 0, width, diff * 3); + ACCUMULATE(accumulator[c], x - 1, 1, width, diff * 5); ACCUMULATE(accumulator[c], x, 1, width, diff * 5); - ACCUMULATE(accumulator[c], x + 1, 1, width, diff * 1); + ACCUMULATE(accumulator[c], x + 1, 1, width, diff * 3); } // Write the newly produced pixel -- cgit v0.12