From fffbf48dec317d55262de62f8bab757a31d0eebd Mon Sep 17 00:00:00 2001
From: raysan5 <raysan5@gmail.com>
Date: Wed, 2 Mar 2016 19:22:55 +0100
Subject: [PATCH] Added support for Nearest-Neighbor image scaling

Specially useful on default font scaling
---
 src/raylib.h   |  1 +
 src/textures.c | 38 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/raylib.h b/src/raylib.h
index 4f36e203f..f8f1683e3 100644
--- a/src/raylib.h
+++ b/src/raylib.h
@@ -691,6 +691,7 @@ void ImageDither(Image *image, int rBpp, int gBpp, int bBpp, int aBpp);
 Image ImageCopy(Image image);                                                                      // Create an image duplicate (useful for transformations)
 void ImageCrop(Image *image, Rectangle crop);                                                      // Crop an image to a defined rectangle
 void ImageResize(Image *image, int newWidth, int newHeight);                                       // Resize and image (bilinear filtering)
+void ImageResizeNN(Image *image,int newWidth,int newHeight);                                       // Resize and image (Nearest-Neighbor scaling algorithm)
 void ImageDraw(Image *dst, Image src, Rectangle srcRec, Rectangle dstRec);                         // Draw a source image within a destination image
 Image ImageText(const char *text, int fontSize, Color color);                                      // Create an image from text (default font)
 Image ImageTextEx(SpriteFont font, const char *text, int fontSize, int spacing, Color tint);       // Create an image from text (custom sprite font)
diff --git a/src/textures.c b/src/textures.c
index 36819daf4..cb3113dc4 100644
--- a/src/textures.c
+++ b/src/textures.c
@@ -919,6 +919,39 @@ void ImageResize(Image *image, int newWidth, int newHeight)
     free(pixels);
 }
 
+// Resize and image to new size using Nearest-Neighbor scaling algorithm
+void ImageResizeNN(Image *image,int newWidth,int newHeight) 
+{
+    Color *pixels = GetImageData(*image);
+    Color *output = (Color *)malloc(newWidth*newHeight*sizeof(Color));
+    
+    // EDIT: added +1 to account for an early rounding problem
+    int x_ratio = (int)((image->width<<16)/newWidth) + 1;
+    int y_ratio = (int)((image->height<<16)/newHeight) + 1;
+    
+    int x2, y2;
+    for (int i = 0; i < newHeight; i++) 
+    {
+        for (int j = 0; j < newWidth; j++) 
+        {
+            x2 = ((j*x_ratio) >> 16);
+            y2 = ((i*y_ratio) >> 16);
+            
+            output[(i*newWidth) + j] = pixels[(y2*image->width) + x2] ;
+        }                
+    }                
+
+    int format = image->format;
+
+    UnloadImage(*image);
+
+    *image = LoadImageEx(output, newWidth, newHeight);
+    ImageFormat(image, format);  // Reformat 32bit RGBA image to original format 
+    
+    free(output);
+    free(pixels);
+}
+
 // Draw an image (source) within an image (destination)
 void ImageDraw(Image *dst, Image src, Rectangle srcRec, Rectangle dstRec) 
 {
@@ -1046,8 +1079,9 @@ Image ImageTextEx(SpriteFont font, const char *text, int fontSize, int spacing,
         float scaleFactor = (float)fontSize/imSize.y;
         TraceLog(INFO, "Scalefactor: %f", scaleFactor);
         
-        // TODO: Allow nearest-neighbor scaling algorithm
-        ImageResize(&imText, (int)(imSize.x*scaleFactor), (int)(imSize.y*scaleFactor)); 
+        // Using nearest-neighbor scaling algorithm for default font
+        if (font.texture.id == GetDefaultFont().texture.id) ImageResizeNN(&imText, (int)(imSize.x*scaleFactor), (int)(imSize.y*scaleFactor));
+        else ImageResize(&imText, (int)(imSize.x*scaleFactor), (int)(imSize.y*scaleFactor));
     }
     
     free(pixels);