Changeset 8d3512f1 in mainline for uspace/lib/softrend/filter.c

Timestamp:

2014-08-31T14:53:51Z (11 years ago)

Author:

Martin Sucha <sucha14@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

00ddb40

Parents:

c6c39d4f

Message:

Implement a bilinear filter and use it when compositing windows.

File:

• uspace/lib/softrend/filter.c (modified) (2 diffs)

uspace/lib/softrend/filter.c

@@ -1 +1 @@
 /*
  * Copyright (c) 2012 Petr Koupy
+ * Copyright (c) 2014 Martin Sucha
  * All rights reserved.
  *
@@ -35 +36 @@
 
 #include "filter.h"
+#include <io/pixel.h>
+
+static long round(double val)
+{
+        return val > 0 ? (long) (val + 0.5) : (long) (val - 0.5);
+}
+
+static long floor(double val)
+{
+        long lval = (long) val;
+        if (val < 0 && lval != val)
+                return lval - 1;
+        return lval;
+}
+
+static long ceil(double val)
+{
+        long lval = (long) val;
+        if (val > 0 && lval != val)
+                return lval + 1;
+        return lval;
+}
+
+static pixel_t get_pixel(pixelmap_t *pixmap, sysarg_t x, sysarg_t y, bool tile)
+{
+        if (tile) {
+                x %= pixmap->width;
+                y %= pixmap->height;
+        }
+
+        return pixelmap_get_pixel(pixmap, (sysarg_t) x, (sysarg_t) y);
+}
+
+static inline pixel_t blend_pixels(size_t count, float *weights,
+    pixel_t *pixels)
+{
+        float alpha = 0, red = 0, green = 0, blue = 0;
+        for (size_t index = 0; index < count; index++) {
+                alpha += weights[index] * ALPHA(pixels[index]);
+                red   += weights[index] *   RED(pixels[index]);
+                green += weights[index] * GREEN(pixels[index]);
+                blue  += weights[index] *  BLUE(pixels[index]);
+        }
+        
+        return PIXEL((uint8_t) alpha, (uint8_t) red, (uint8_t) green,
+            (uint8_t) blue);
+}
 
 pixel_t filter_nearest(pixelmap_t *pixmap, double x, double y, bool tile)
 {
-        long _x = x > 0 ? (long) (x + 0.5) : (long) (x - 0.5);
-        long _y = y > 0 ? (long) (y + 0.5) : (long) (y - 0.5);
-
-        if (tile) {
-                _x %= pixmap->width;
-                _y %= pixmap->height;
-        }
-
-        return pixelmap_get_pixel(pixmap, (sysarg_t) _x, (sysarg_t) _y);
+        return get_pixel(pixmap, round(x), round(y), tile);
 }
 
 pixel_t filter_bilinear(pixelmap_t *pixmap, double x, double y, bool tile)
 {
-        // TODO
-        return 0;
+        long x1 = floor(x);
+        long x2 = ceil(x);
+        long y1 = floor(y);
+        long y2 = ceil(y);
+        
+        if (y1 == y2 && x1 == x2) {
+                return get_pixel(pixmap, (sysarg_t) x1, (sysarg_t) y1,
+                    tile);
+        }
+        
+        double x_delta = x - x1;
+        double y_delta = y - y1;
+        
+        pixel_t pixels[4];
+        pixels[0] = get_pixel(pixmap, x1, y1, tile);
+        pixels[1] = get_pixel(pixmap, x2, y1, tile);
+        pixels[2] = get_pixel(pixmap, x1, y2, tile);
+        pixels[3] = get_pixel(pixmap, x2, y2, tile);
+        
+        float weights[4];
+        weights[0] = (1 - x_delta) * (1 - y_delta);
+        weights[1] = (    x_delta) * (1 - y_delta);
+        weights[2] = (1 - x_delta) * (    y_delta);
+        weights[3] = (    x_delta) * (    y_delta);
+        
+        return blend_pixels(4, weights, pixels);
 }