diff options
Diffstat (limited to 'src/display/pixblock-scaler.cpp')
| -rw-r--r-- | src/display/pixblock-scaler.cpp | 87 |
1 files changed, 82 insertions, 5 deletions
diff --git a/src/display/pixblock-scaler.cpp b/src/display/pixblock-scaler.cpp index d65cfd4e0..ddb4c4ee2 100644 --- a/src/display/pixblock-scaler.cpp +++ b/src/display/pixblock-scaler.cpp @@ -34,7 +34,7 @@ struct RGBA { * decimal part. (24.8 assuming 32-bit int) */ __attribute__ ((const)) -inline int sampley(unsigned const char a, unsigned const char b, +inline static int sampley(unsigned const char a, unsigned const char b, unsigned const char c, unsigned const char d, const double len) { @@ -62,7 +62,7 @@ inline int sampley(unsigned const char a, unsigned const char b, * Returns the interpolated value in 8-bit format, ready to be written * to output buffer. */ -inline int samplex(const int a, const int b, const int c, const int d, const double len) { +inline static int samplex(const int a, const int b, const int c, const int d, const double len) { double lenf = len - floor(len); int sum = 0; sum += (int)(a * (((-1.0 / 3.0) * lenf + 4.0 / 5.0) * lenf - 7.0 / 15.0) * lenf); @@ -79,7 +79,7 @@ inline int samplex(const int a, const int b, const int c, const int d, const dou * Catches reading and writing outside the pixblock area. * When enabled, decreases filter rendering speed massively. */ -inline void _check_index(NRPixBlock const * const pb, int const location, int const line) +inline static void _check_index(NRPixBlock const * const pb, int const location, int const line) { if(false) { int max_loc = pb->rs * (pb->area.y1 - pb->area.y0); @@ -88,10 +88,10 @@ inline void _check_index(NRPixBlock const * const pb, int const location, int co } } -void scale_bicubic(NRPixBlock *to, NRPixBlock *from) +static void scale_bicubic_rgba(NRPixBlock *to, NRPixBlock *from) { if (NR_PIXBLOCK_BPP(from) != 4 || NR_PIXBLOCK_BPP(to) != 4) { - g_warning("A non-32-bpp image passed to scale_bicubic: scaling aborted."); + g_warning("A non-32-bpp image passed to scale_bicubic_rgba: scaling aborted."); return; } @@ -192,6 +192,83 @@ void scale_bicubic(NRPixBlock *to, NRPixBlock *from) } } +void scale_bicubic_alpha(NRPixBlock *to, NRPixBlock *from) +{ + if (NR_PIXBLOCK_BPP(from) != 1 || NR_PIXBLOCK_BPP(to) != 1) { + g_warning("A non-8-bpp image passed to scale_bicubic_alpha: scaling aborted."); + return; + } + + // Precalculate sizes of source and destination pixblocks + int from_width = from->area.x1 - from->area.x0; + int from_height = from->area.y1 - from->area.y0; + int to_width = to->area.x1 - to->area.x0; + int to_height = to->area.y1 - to->area.y0; + + // from_step: when advancing one pixel in destination image, + // how much we should advance in source image + double from_stepx = (double)from_width / (double)to_width; + double from_stepy = (double)from_height / (double)to_height; + + // Loop through every pixel of destination image, a line at a time + for (int to_y = 0 ; to_y < to_height ; to_y++) { + double from_y = to_y * from_stepy + from_stepy / 2; + // Pre-calculate beginning of the four horizontal lines, from + // which we should read + int from_line[4]; + for (int i = 0 ; i < 4 ; i++) { + if ((int)floor(from_y) + i - 1 >= 0) { + if ((int)floor(from_y) + i - 1 < from_height) { + from_line[i] = ((int)floor(from_y) + i - 1) * from->rs; + } else { + from_line[i] = (from_height - 1) * from->rs; + } + } else { + from_line[i] = 0; + } + } + // Loop through this horizontal line in destination image + // For every pixel, calculate the color of pixel with + // bicubic interpolation and set the pixel value in destination image + for (int to_x = 0 ; to_x < to_width ; to_x++) { + double from_x = to_x * from_stepx + from_stepx / 2; + int line[4]; + for (int i = 0 ; i < 4 ; i++) { + int k = (int)floor(from_x) + i - 1; + if (k < 0) k = 0; + if (k >= from_width) k = from_width - 1; + _check_index(from, from_line[0] + k, __LINE__); + _check_index(from, from_line[1] + k, __LINE__); + _check_index(from, from_line[2] + k, __LINE__); + _check_index(from, from_line[3] + k, __LINE__); + line[i] = sampley(NR_PIXBLOCK_PX(from)[from_line[0] + k], + NR_PIXBLOCK_PX(from)[from_line[1] + k], + NR_PIXBLOCK_PX(from)[from_line[2] + k], + NR_PIXBLOCK_PX(from)[from_line[3] + k], + from_y); + } + int result; + result = samplex(line[0], line[1], line[2], line[3], + from_x); + + _check_index(to, to_y * to->rs + to_x, __LINE__); + + NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x] = clamp(result); + } + } +} + +void scale_bicubic(NRPixBlock *to, NRPixBlock *from) +{ + if (NR_PIXBLOCK_BPP(to) == 4 && NR_PIXBLOCK_BPP(from) == 4) { + scale_bicubic_rgba(to, from); + } else if (NR_PIXBLOCK_BPP(to) == 1 && NR_PIXBLOCK_BPP(from) == 1) { + scale_bicubic_alpha(to, from); + } else { + g_warning("NR::scale_bicubic: unsupported bitdepths for scaling: to %d, from %d", NR_PIXBLOCK_BPP(to), NR_PIXBLOCK_BPP(from)); + } +} + } /* namespace NR */ /* Local Variables: |