Diff: bmp.cpp

Revision:

0:b567d56a59d7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/bmp.cpp	Fri Oct 03 13:30:09 2014 +0000
@@ -0,0 +1,215 @@
+/* ----------------------------------------------------------------------------
+ *         ATMEL Microcontroller Software Support  -  ROUSSET  -
+ * ----------------------------------------------------------------------------
+ * Copyright (c) 2006, Atmel Corporation
+
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the disclaiimer below.
+ * 
+ * - Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the disclaimer below in the documentation and/or
+ * other materials provided with the distribution. 
+ * 
+ * Atmel's name may not be used to endorse or promote products derived from
+ * this software without specific prior written permission. 
+ * 
+ * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
+ * DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ----------------------------------------------------------------------------
+ */
+
+//------------------------------------------------------------------------------
+//         Headers
+//------------------------------------------------------------------------------
+
+#include "mbed.h"
+#include "bmp.h"
+
+//------------------------------------------------------------------------------
+//         Internal constants
+//------------------------------------------------------------------------------
+
+/// BMP magic number ('BM').
+#define BMP_TYPE        0x4D42
+
+//------------------------------------------------------------------------------
+//         Internal types
+//------------------------------------------------------------------------------
+
+struct BMPPaletteEntry {
+
+    unsigned char b;
+    unsigned char g;
+    unsigned char r;
+    unsigned char filler;
+};
+
+//------------------------------------------------------------------------------
+//         Exported functions
+//------------------------------------------------------------------------------
+
+//------------------------------------------------------------------------------
+/// Returns 1 if the header of a BMP file is valid; otherwise returns 0.
+/// \param file  Buffer holding the file to examinate.
+//------------------------------------------------------------------------------
+unsigned char BMP_IsValid(void *file)
+{
+    return ((struct BMPHeader *) file)->type == BMP_TYPE;
+}
+
+//------------------------------------------------------------------------------
+/// Returns the size of a BMP image given at least its header (the file does
+/// not have to be complete).
+/// \param file  Pointer to the buffer which holds the BMP file.
+//------------------------------------------------------------------------------
+unsigned int BMP_GetFileSize(void *file)
+{
+    return ((struct BMPHeader *) file)->fileSize;
+}
+
+//------------------------------------------------------------------------------
+/// Loads a BMP image located at the given address, decodes it and stores the
+/// resulting image inside the provided buffer. Image must have the specified
+/// width & height.
+/// Returns 0 if the image has been loaded; otherwise returns an error code.
+/// \param file  Buffer which holds the BMP file.
+/// \param buffer  Buffer in which to store the decoded image.
+/// \param width  Buffer width in pixels.
+/// \param height  Buffer height in pixels.
+/// \param bpp  Number of bits per pixels that the buffer stores.
+//------------------------------------------------------------------------------
+unsigned char BMP_Decode(
+    void *file,
+    unsigned char *buffer,
+    unsigned int width,
+    unsigned int height,
+    unsigned char bpp)
+{
+    struct BMPHeader *header;
+    unsigned int i, j;
+    unsigned char r, g, b;
+    unsigned char *image;
+
+  // Read header information
+    header = (struct BMPHeader *) file;
+
+    // Verify that the file is valid
+    if (!BMP_IsValid(file)) {
+
+        printf("BMP_Decode: File type is not 'BM' (0x%x).\n\r",
+                header->type);
+        return 1;
+    }
+    
+    // Check that parameters match
+    if ((header->compression != 0)
+        || (header->width != width)
+        || (header->height != height)) {
+
+        printf("BMP_Decode: File format not supported\n\r");
+        printf(" -> .compression = %d\n\r", header->compression);
+        printf(" -> .width = %d\n\r", header->width);
+        printf(" -> .height = %d\n\r", header->height);
+        printf(" -> .bits = %d\n\r", header->bits);
+        return 2;
+    }
+
+    // Get image data
+    image = (unsigned char *) ((unsigned int) file + header->offset);
+
+    // Check that the bpp resolution is supported
+    // Only a 24-bit output & 24- or 8-bit input are supported
+    if (bpp != 24) {
+
+        printf("BMP_Decode: Output resolution not supported\n\r");
+        return 3;
+    }
+    else if (header->bits == 24) {
+    
+        // Modified by Embedded Artists. This padding was not handled in the original
+        // implementation. Each row in the Pixel Array is padded to a multiple of 4 bytes in size
+        int rowWidthBytes = width * 3;
+        rowWidthBytes += (rowWidthBytes % 4);
+
+        // Copy raw data from BMP to buffer (reversing row order)
+        for (i=0; i < height; i++) {
+#if 1
+          // Modified by Embedded Artists to convert to 565-format instead of 24 bit
+          int x;
+          for(x=0; x<width; x++)
+          {          
+            r = *(unsigned char *)(image + (height - i - 1) * rowWidthBytes + 3*x + 2);
+            g = *(unsigned char *)(image + (height - i - 1) * rowWidthBytes + 3*x + 1);
+            b = *(unsigned char *)(image + (height - i - 1) * rowWidthBytes + 3*x + 0);
+            *(unsigned short *)(buffer + (i * width) * 2 + 2*x) = (((unsigned short)r & 0xF8) << 8) |
+                                                                  (((unsigned short)g & 0xFC) << 3) |
+                                                                  (((unsigned short)b & 0xF8) >> 3);
+          }
+#else
+            memcpy(buffer + (i * width) * 3,
+                   image + ((height - i - 1) * width) * 3,
+                   width * 3);
+#endif
+        }
+
+#if 0
+        // Swap red and blue
+        for (i=0; i < height; i++) {
+            for (j=0; j < width; j++) {
+
+                r = buffer[(i * width + j) * 3 + 2];
+                g = buffer[(i * width + j) * 3 + 1];
+                b = buffer[(i * width + j) * 3];
+
+                buffer[(i * width + j) * 3] = r;
+                buffer[(i * width + j) * 3 + 1] = g;
+                buffer[(i * width + j) * 3 + 2] = b;
+            }
+        }
+#endif
+    }
+    else if (header->bits == 8) {
+
+        // Retrieve palette
+        struct BMPPaletteEntry palette[256];
+        memcpy(palette,
+               (unsigned char *) ((unsigned int) file + sizeof(struct BMPHeader)),
+               header->offset - sizeof(struct BMPHeader));
+
+        // Decode image (reversing row order)
+        for (i=0; i < height; i++) {
+            for (j=0; j < width; j++) {
+
+                r = palette[image[(height - i - 1) * width + j]].r;
+                g = palette[image[(height - i - 1) * width + j]].g;
+                b = palette[image[(height - i - 1) * width + j]].b;
+
+                buffer[(i * width + j) * 3] = r;
+                buffer[(i * width + j) * 3 + 1] = g;
+                buffer[(i * width + j) * 3 + 2] = b;
+            }
+        }
+    }
+    else {
+
+        printf("BMP_Decode: Input resolution not supported\n\r");
+        return 4;
+    }
+
+    return 0;
+}
+
+