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commit 4570f19440d0f99e3b301ebf1c51ed19a3d0ba6b
parent 4387bd7a0eba82a2d5d7250f7d2be32cd7e29b50
Author: Anton Kindestam <antonki@kth.se>
Date:   Tue,  5 Sep 2017 11:27:14 +0200

[sent] Add bilinear scaling patch

Diffstat:
Atools.suckless.org/sent/patches/bilinear_scaling.md | 33+++++++++++++++++++++++++++++++++
Atools.suckless.org/sent/patches/sent-bilinearscaling-1.0.diff | 88+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 121 insertions(+), 0 deletions(-)

diff --git a/tools.suckless.org/sent/patches/bilinear_scaling.md b/tools.suckless.org/sent/patches/bilinear_scaling.md @@ -0,0 +1,33 @@ +Use Bilinear Scaling for Image Slides +===================================== + +Description +----------- + +The patch replaces the Nearest Neighbor Scaling algorithm used for +images with Bilinear Scaling. + +This should give somewhat more pleasing results when using image +slides for graphs, or other material which suffers badly under +aliasing. + +Notes +----- + +Due to the nature of Bilinear Scaling, scaling down more than 50% will +have somewhat less pleasing results. Scaling up will generally be +quite blurry. + +There is room for further improvement of image scaling, e.g: +Implementing a better scaling algorithm such as bicubic, or lancszos; +and/or using separate algorithms for scaling up or down. + +Download +-------- + +* [sent-bilinearscaling-1.0.diff](sent-bilinearscaling-1.0.diff) + +Author +------ + +* Anton Kindestam (xantoz) <antonki@kth.se> diff --git a/tools.suckless.org/sent/patches/sent-bilinearscaling-1.0.diff b/tools.suckless.org/sent/patches/sent-bilinearscaling-1.0.diff @@ -0,0 +1,88 @@ +diff --git a/sent.c b/sent.c +index 0da2bff..d92cf3b 100644 +--- a/sent.c ++++ b/sent.c +@@ -282,27 +282,66 @@ ffprepare(Image *img) + img->state |= SCALED; + } + ++static unsigned char double_to_uchar_clamp255(double dbl) ++{ ++ dbl = round(dbl); ++ ++ return ++ (dbl < 0.0) ? 0 : ++ (dbl > 255.0) ? 255 : (unsigned char)dbl; ++} ++ ++static int int_clamp(int integer, int lower, int upper) ++{ ++ if (integer < lower) ++ return lower; ++ else if (integer >= upper) ++ return upper - 1; ++ else ++ return integer; ++} ++ + void + ffscale(Image *img) + { +- unsigned int x, y; +- unsigned int width = img->ximg->width; +- unsigned int height = img->ximg->height; +- char* newBuf = img->ximg->data; +- unsigned char* ibuf; +- unsigned int jdy = img->ximg->bytes_per_line / 4 - width; +- unsigned int dx = (img->bufwidth << 10) / width; +- +- for (y = 0; y < height; y++) { +- unsigned int bufx = img->bufwidth / width; +- ibuf = &img->buf[y * img->bufheight / height * img->bufwidth * 3]; +- +- for (x = 0; x < width; x++) { +- *newBuf++ = (ibuf[(bufx >> 10)*3+2]); +- *newBuf++ = (ibuf[(bufx >> 10)*3+1]); +- *newBuf++ = (ibuf[(bufx >> 10)*3+0]); ++ const unsigned width = img->ximg->width; ++ const unsigned height = img->ximg->height; ++ unsigned char* newBuf = (unsigned char*)img->ximg->data; ++ const unsigned jdy = img->ximg->bytes_per_line / 4 - width; ++ ++ const double x_scale = ((double)img->bufwidth/(double)width); ++ const double y_scale = ((double)img->bufheight/(double)height); ++ ++ for (unsigned y = 0; y < height; ++y) { ++ const double old_y = (double)y * y_scale; ++ const double y_factor = ceil(old_y) - old_y; ++ const int old_y_int_0 = int_clamp((int)floor(old_y), 0, img->bufheight); ++ const int old_y_int_1 = int_clamp((int)ceil(old_y), 0, img->bufheight); ++ ++ for (unsigned x = 0; x < width; ++x) { ++ const double old_x = (double)x * x_scale; ++ const double x_factor = ceil(old_x) - old_x; ++ const int old_x_int_0 = int_clamp((int)floor(old_x), 0, img->bufwidth); ++ const int old_x_int_1 = int_clamp((int)ceil(old_x), 0, img->bufwidth); ++ ++ const unsigned c00_pos = 3*((old_x_int_0) + ((old_y_int_0)*img->bufwidth)); ++ const unsigned c01_pos = 3*((old_x_int_0) + ((old_y_int_1)*img->bufwidth)); ++ const unsigned c10_pos = 3*((old_x_int_1) + ((old_y_int_0)*img->bufwidth)); ++ const unsigned c11_pos = 3*((old_x_int_1) + ((old_y_int_1)*img->bufwidth)); ++ ++ for (int i = 2; i >= 0 ; --i) { ++ const unsigned char c00 = img->buf[c00_pos + i]; ++ const unsigned char c01 = img->buf[c01_pos + i]; ++ const unsigned char c10 = img->buf[c10_pos + i]; ++ const unsigned char c11 = img->buf[c11_pos + i]; ++ ++ const double x_result_0 = (double)c00*x_factor + (double)c10*(1.0 - x_factor); ++ const double x_result_1 = (double)c01*x_factor + (double)c11*(1.0 - x_factor); ++ const double result = x_result_0*y_factor + x_result_1*(1.0 - y_factor); ++ ++ *newBuf++ = double_to_uchar_clamp255(result); ++ } + newBuf++; +- bufx += dx; + } + newBuf += jdy; + }