libvpx: Add VP9 decoder.

source/libvpx/vp9/common/vp9_textblit.c

+/*
+ *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <stdlib.h>
+
+#include "vp9/common/vp9_textblit.h"
+
+void vp9_blit_text(const char *msg, unsigned char *address, const int pitch) {
+  int letter_bitmap;
+  unsigned char *output_pos = address;
+  int colpos;
+  const int font[] = {
+    0x0, 0x5C00, 0x8020, 0xAFABEA, 0xD7EC0, 0x1111111, 0x1855740, 0x18000,
+    0x45C0, 0x74400, 0x51140, 0x23880, 0xC4000, 0x21080, 0x80000, 0x111110,
+    0xE9D72E, 0x87E40, 0x12AD732, 0xAAD62A, 0x4F94C4, 0x4D6B7, 0x456AA,
+    0x3E8423, 0xAAD6AA, 0xAAD6A2, 0x2800, 0x2A00, 0x8A880, 0x52940, 0x22A20,
+    0x15422, 0x6AD62E, 0x1E4A53E, 0xAAD6BF, 0x8C62E, 0xE8C63F, 0x118D6BF,
+    0x1094BF, 0xCAC62E, 0x1F2109F, 0x118FE31, 0xF8C628, 0x8A89F, 0x108421F,
+    0x1F1105F, 0x1F4105F, 0xE8C62E, 0x2294BF, 0x164C62E, 0x12694BF, 0x8AD6A2,
+    0x10FC21, 0x1F8421F, 0x744107, 0xF8220F, 0x1151151, 0x117041, 0x119D731,
+    0x47E0, 0x1041041, 0xFC400, 0x10440, 0x1084210, 0x820
+  };
+  colpos = 0;
+
+  while (msg[colpos] != 0) {
+    char letter = msg[colpos];
+    int fontcol, fontrow;
+
+    if (letter <= 'Z' && letter >= ' ')
+      letter_bitmap = font[letter - ' '];
+    else if (letter <= 'z' && letter >= 'a')
+      letter_bitmap = font[letter - 'a' + 'A' - ' '];
+    else
+      letter_bitmap = font[0];
+
+    for (fontcol = 6; fontcol >= 0; fontcol--)
+      for (fontrow = 0; fontrow < 5; fontrow++)
+        output_pos[fontrow * pitch + fontcol] =
+          ((letter_bitmap >> (fontcol * 5)) & (1 << fontrow) ? 255 : 0);
+
+    output_pos += 7;
+    colpos++;
+  }
+}
+
+static void plot(const int x, const int y, unsigned char *image, const int pitch) {
+  image [x + y * pitch] ^= 255;
+}
+
+/* Bresenham line algorithm */
+void vp9_blit_line(int x0, int x1, int y0, int y1, unsigned char *image, const int pitch) {
+  int steep = abs(y1 - y0) > abs(x1 - x0);
+  int deltax, deltay;
+  int error, ystep, y, x;
+
+  if (steep) {
+    int t;
+    t = x0;
+    x0 = y0;
+    y0 = t;
+
+    t = x1;
+    x1 = y1;
+    y1 = t;
+  }
+
+  if (x0 > x1) {
+    int t;
+    t = x0;
+    x0 = x1;
+    x1 = t;
+
+    t = y0;
+    y0 = y1;
+    y1 = t;
+  }
+
+  deltax = x1 - x0;
+  deltay = abs(y1 - y0);
+  error  = deltax / 2;
+
+  y = y0;
+
+  if (y0 < y1)
+    ystep = 1;
+  else
+    ystep = -1;
+
+  if (steep) {
+    for (x = x0; x <= x1; x++) {
+      plot(y, x, image, pitch);
+
+      error = error - deltay;
+      if (error < 0) {
+        y = y + ystep;
+        error = error + deltax;
+      }
+    }
+  } else {
+    for (x = x0; x <= x1; x++) {
+      plot(x, y, image, pitch);
+
+      error = error - deltay;
+      if (error < 0) {
+        y = y + ystep;
+        error = error + deltax;
+      }
+    }
+  }
+}