<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_REOPENED " title="REOPENED --- - Add option to manually disable bilinear filtering" href="https://bugs.freedesktop.org/show_bug.cgi?id=68360#c23">Comment # 23</a> on <a class="bz_bug_link bz_status_REOPENED " title="REOPENED --- - Add option to manually disable bilinear filtering" href="https://bugs.freedesktop.org/show_bug.cgi?id=68360">bug 68360</a> from <a class="email" href="mailto:dr.hyder@gmail.com" title="Charles Hyder <dr.hyder@gmail.com>"> Charles Hyder</a> <pre>I'm going to start with rewriting a pair of functions (both defined in Splash.cc) that implement bilinear interpolation: static void expandRow(Guchar *srcBuf, Guchar *dstBuf, int srcWidth, int scaledWidth, int nComps) void Splash::scaleImageYuXuBilinear(SplashImageSource src, void *srcData, SplashColorMode srcMode, int nComps, GBool srcAlpha, int srcWidth, int srcHeight, int scaledWidth, int scaledHeight, SplashBitmap *dest) The first one interpolates along x, the second one interpolates along y using results of calling the first one on adjacent rows. There are two problems that I'm going to address: 1) both functions use floating point math, I'm going to replace that with integer point math, fully preserving accuracy and hugely improving the speed; 2) when scaledWidth == srcWidth, scaledHeight == srcHeight, the nodes of the source and destination grids are coinciding, and the interpolation should (mathematically speaking) produce an identical image. So, I suspect, there is indeed a bug after all. I'm going to find it. Once I solve both problems the status of the bug will be as follows: 1) the original issue (bug) of fuzzy rendering at scale = 1 will be resolved; 2) For scale > 1 the rendering of images will be done as before, but at improved speed. In particular, at 1 < scale < 4 (4 is an AD HOC number introduced previously by someone else) the rendering will be done using interpolation REGARDLESS of whether the "interpolate" flag is set. I consider the last point a (minor) bug as well, but the one that doesn't bother me personally. I'm not going to address it. In summary: I'm going to 1) improve speed of image rendering at scale > 1, while not altering what is produced - images produced will be interpolated for 1 < scale < 4, as before; 2) I'm going to fix interpolation at scale = 1: the image should just be copied 1-to-1 in this case, obviously.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>