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62 lines
No EOL
1.6 KiB
C++
62 lines
No EOL
1.6 KiB
C++
#include "bicubic.h"
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#if 1
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static int sGetA(int a, int src, int tgt, int method)
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{
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if(method != DOWNSCALE_WIDE)
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return a;
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return max(src / tgt, 1) * a;
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}
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Image RescaleWithKernelE(const Image& _img, int cx, int cy, double (*kernel)(double x), int a,
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int method)
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{
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Image img = _img;
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Size isz = img.GetSize();
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if(method == DOWNSCALE_MIPMAP) {
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Size sz = isz / Size(cx, cy);
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if(sz.cx >= a || sz.cy >= a) {
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img = DownScale(img, max(sz.cx, 1), max(sz.cy, 1));
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isz = img.GetSize();
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}
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}
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ImageBuffer ib(cx, cy);
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RGBA *t = ~ib;
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int ax = sGetA(a, isz.cx, cx, method);
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int ay = sGetA(a, isz.cy, cy, method);
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double inv_cx = 1.0 / cx;
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for(int y = 0; y < cy; y++) {
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int sy = (y * isz.cy) / cy;
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double dy = y * isz.cy / (double)cy - sy;
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for(int x = 0; x < cx; x++) {
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int sx = (x * isz.cx) / cx;
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double dx = x * isz.cx * inv_cx - sx;
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double red = 0;
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double green = 0;
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double blue = 0;
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double alpha = 0;
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double w = 0;
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for(int yy = -ay + 1; yy <= ay; yy++) {
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double ky = kernel((yy - dy) * a / ay);
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const RGBA *l = img[minmax(sy + yy, 0, isz.cy - 1)];
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for(int xx = -ax + 1; xx <= ax; xx++) {
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const RGBA& s = l[minmax(sx + xx, 0, isz.cx - 1)];
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double weight = ky * kernel((xx - dx) * a / ax);
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red += weight * s.r;
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green += weight * s.g;
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blue += weight * s.b;
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alpha += weight * s.a;
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w += weight;
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}
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}
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t->r = Saturate255((int)(red / w));
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t->g = Saturate255((int)(green / w));
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t->b = Saturate255((int)(blue / w));
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t->a = Saturate255((int)(alpha / w));
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t++;
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}
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}
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return ib;
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}
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#endif |