Search found 4 matches

by yoya
2013-10-24T23:42:31-07:00
Forum: Developers
Topic: Proposal: Quantize Bulk Reduce Acceleration
Replies: 1
Views: 5030

Proposal: Quantize Bulk Reduce Acceleration

Hi, all. I would like to propose QBRA (Quantize Bulk Reduce Acceleration) configuration to enable rapid color reduction. The explanation of idea is here. - http://d.hatena.ne.jp/yoya/20130724/im With only a small code addition and without changing the fundamental algorithm we can get a performance b...
by yoya
2013-07-13T11:40:39-07:00
Forum: Developers
Topic: miscalculation of summarized quantize_error
Replies: 3
Views: 6417

Re: miscalculation of summarized quantize_error

Thank you for your quick response. At 6.8.6-5, this modified code has wrong calculation. node_info->quantize_error+=count*sqrt((double) (error.red*error.red+ count*error.green*error.green+count*error.blue*error.blue+ count*error.opacity*error.opacity)); In sqrt all count multiplication must be remov...
by yoya
2013-07-12T02:51:54-07:00
Forum: Developers
Topic: quantize tree walking mistake for RiemersmaDither
Replies: 1
Views: 4243

quantize tree walking mistake for RiemersmaDither

I found tree walking mistake for RiemersmaDither function. * ImageMagick-6.8.6-4/magick/quantize.c /* Identify the deepest node containing the pixel's color. */ node_info=p->root; for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--) { id=ColorToNodeId(cube_info,&pixel,index); if (node_info->chil...
by yoya
2013-07-11T23:31:41-07:00
Forum: Developers
Topic: miscalculation of summarized quantize_error
Replies: 3
Views: 6417

miscalculation of summarized quantize_error

quantize_error summarization has been changed at 6.4.1-3 * magick/quantize.c - 6.4.1-2 node_info->quantize_error+=sqrt((double) (error.red*error.red+ error.green*error.green+error.blue*error.blue+error.opacity* error.opacity)); - 6.4.1-3 if (IsColorSimilar(image,p,p+count) == MagickFalse) break; (om...