From d00f0a1ccd2a9b1c332bbf7754f291dd61dee14f Mon Sep 17 00:00:00 2001
From: Joseph Redmon <pjreddie@gmail.com>
Date: Tue, 21 Jul 2015 23:09:33 +0000
Subject: [PATCH] Changes to make routing work better

---
 src/image.c |   45 +++++++++++++++++++++++++++++++++++++--------
 1 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/src/image.c b/src/image.c
index 046de0c..ae8ca0a 100644
--- a/src/image.c
+++ b/src/image.c
@@ -332,7 +332,7 @@
             for(x = 0; x < im.w; ++x){
                 float rx = cos(rad)*(x-cx) - sin(rad)*(y-cy) + cx;
                 float ry = sin(rad)*(x-cx) + cos(rad)*(y-cy) + cy;
-                float val = billinear_interpolate(im, rx, ry, c);
+                float val = bilinear_interpolate(im, rx, ry, c);
                 set_pixel(rot, x, y, c, val);
             }
         }
@@ -549,7 +549,7 @@
    }
  */
 
-float billinear_interpolate(image im, float x, float y, int c)
+float bilinear_interpolate(image im, float x, float y, int c)
 {
     int ix = (int) floorf(x);
     int iy = (int) floorf(y);
@@ -564,23 +564,47 @@
     return val;
 }
 
-// #wikipedia
 image resize_image(image im, int w, int h)
 {
     image resized = make_image(w, h, im.c);   
+    image part = make_image(w, im.h, im.c);
     int r, c, k;
     float w_scale = (float)(im.w - 1) / (w - 1);
     float h_scale = (float)(im.h - 1) / (h - 1);
     for(k = 0; k < im.c; ++k){
-        for(r = 0; r < h; ++r){
+        for(r = 0; r < im.h; ++r){
             for(c = 0; c < w; ++c){
-                float sx = c*w_scale;
-                float sy = r*h_scale;
-                float val = billinear_interpolate(im, sx, sy, k);
-                set_pixel(resized, c, r, k, val);
+                float val = 0;
+                if(c == w-1){
+                    val = get_pixel(im, im.w-1, r, k);
+                } else {
+                    float sx = c*w_scale;
+                    int ix = (int) sx;
+                    float dx = sx - ix;
+                    val = (1 - dx) * get_pixel(im, ix, r, k) + dx * get_pixel(im, ix+1, r, k);
+                }
+                set_pixel(part, c, r, k, val);
             }
         }
     }
+    for(k = 0; k < im.c; ++k){
+        for(r = 0; r < h; ++r){
+            float sy = r*h_scale;
+            int iy = (int) sy;
+            float dy = sy - iy;
+            for(c = 0; c < w; ++c){
+                float val = (1-dy) * get_pixel(part, c, iy, k);
+                set_pixel(resized, c, r, k, val);
+            }
+            if(r == h-1) continue;
+            for(c = 0; c < w; ++c){
+                float val = dy * get_pixel(part, c, iy+1, k);
+                add_pixel(resized, c, r, k, val);
+            }
+        }
+    }
+
+    free_image(part);
     return resized;
 }
 
@@ -728,6 +752,11 @@
     assert(x < m.w && y < m.h && c < m.c);
     m.data[c*m.h*m.w + y*m.w + x] = val;
 }
+void add_pixel(image m, int x, int y, int c, float val)
+{
+    assert(x < m.w && y < m.h && c < m.c);
+    m.data[c*m.h*m.w + y*m.w + x] += val;
+}
 
 void print_image(image m)
 {

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