added BMP class to write a test image - image capturing working!!

git-svn-id: svn://anubis/misc/WebcamTracker@128 bd8a9e45-a331-0410-811e-c64571078777

BMP.cc

@@ -0,0 +1,127 @@
+// BMP.cc
+// extracts/inserts data from/into .bmp file
+// Adapted by Josh Holtrop from the original access_bmp.c by gw
+// Supports reading and creating 24-bit color BMP images
+
+#include "BMP.h"
+#include <stdio.h>
+#include <iostream>
+using namespace std;
+
+BMP::BMP(const char * fileName)
+{
+    open(fileName);
+}
+
+BMP::BMP(const char * fileName, int width, int height, unsigned char * data)
+{
+    create(fileName, width, height, data);
+}
+
+BMP::~BMP()
+{
+    if (m_fp != NULL)
+        close();
+}
+
+bool BMP::open(const char * fileName)
+{
+    size_t bytes_read;
+    m_fp = fopen(fileName, "r+");
+    if (m_fp != NULL)
+    {
+        // read file header
+        bytes_read = fread(&m_header, sizeof(m_header), 1, m_fp);
+        if (m_header.id[0] != 'B' || m_header.id[1] != 'M')
+        {
+            cerr << fileName << " does not appear to be a BMP file." << endl;
+            fclose(m_fp);
+            m_fp = NULL;
+        }
+        // read image information
+        bytes_read = fread(&m_info, sizeof(m_info), 1, m_fp);   
+    }
+    return (m_fp != NULL);
+}
+
+bool BMP::create(const char * fileName, int width, int height,
+                 unsigned char * data)
+{
+    size_t bytes_written;
+    m_fp = fopen(fileName, "w+");
+    if (m_fp != NULL)
+    {
+        /* Initialize the header structure */
+        m_header.id[0] = 'B';
+        m_header.id[1] = 'M';
+        int row_padding = (3 * width) & 0x3;
+        if (row_padding)
+            row_padding = 4 - row_padding;
+        int row_bytes = (3 * width) + row_padding;
+        m_header.file_size = sizeof(m_header) +
+                           sizeof(m_info) +
+                           row_bytes * height;
+        m_header.reserved = 0;
+        m_header.offset = sizeof(m_header) + sizeof(m_info);
+
+        /* Initialize the information structure */
+        m_info.header_size = 40;
+        m_info.width = width;
+        m_info.height = height;
+        m_info.color_planes = 1;
+        m_info.color_depth = 24;
+        m_info.compression = 0;
+        m_info.image_size = 0;
+        m_info.xresolution = 2835;
+        m_info.yresolution = 2835;
+        m_info.num_colors = 0;
+        m_info.num_important_colors = 0;
+
+        /* write them to the file */
+        bytes_written = fwrite(&m_header, sizeof(m_header), 1, m_fp);
+        bytes_written = fwrite(&m_info, sizeof(m_info), 1, m_fp);
+
+        unsigned int zero = 0;
+        unsigned char * data_ptr = data + (3 * width) * (height - 1);
+        for (int i = 0; i < height; i++)
+        {
+            bytes_written = fwrite(data_ptr, 3 * width, 1, m_fp);
+            if (row_padding)
+                bytes_written = fwrite(&zero, row_padding, 1, m_fp);
+            data_ptr -= 3 * width;
+        }
+    }
+    return (m_fp != NULL);
+}
+
+void BMP::read(unsigned char * buf)
+{
+    size_t bytes_read;
+    if (m_fp != NULL)
+    {
+        int row_data_bytes = 3 * m_info.width;
+        int row_padding = row_data_bytes & 0x3;
+        if (row_padding)
+            row_padding = 4 - row_padding;
+        fseek(m_fp,
+              (m_header.offset != 0
+                  ? m_header.offset
+                  : sizeof(m_header) + sizeof(m_info)),
+              SEEK_SET);
+        unsigned char * data_ptr = buf + row_data_bytes * (m_info.height - 1);
+        for (int i = 0; i < m_info.height; i++)
+        {
+            bytes_read = fread(data_ptr, row_data_bytes, 1, m_fp);
+            if (row_padding)
+                fseek(m_fp, row_padding, SEEK_CUR);
+            data_ptr -= row_data_bytes;
+        }
+    }
+}
+
+void BMP::close()
+{
+    if (m_fp != NULL)
+        fclose(m_fp);
+    m_fp = NULL;
+}

BMP.h

@@ -0,0 +1,54 @@
+// BMP.h
+// extracts/inserts data from/into .bmp file
+// Adapted by Josh Holtrop from the original access_bmp.c by gw
+// Supports reading and creating 24-bit color BMP images
+
+#include <stdio.h>
+
+#define BMP_RED 2
+#define BMP_GREEN 1
+#define BMP_BLUE 0
+
+class BMP
+{
+public:
+    typedef struct
+    {
+        char id[2];
+        int file_size;
+        int reserved;
+        int offset;
+    } __attribute__ ((packed)) header_t;
+
+    typedef struct
+    {
+        int header_size;
+        int width;
+        int height;
+        unsigned short int color_planes;
+        unsigned short int color_depth;
+        unsigned int compression;
+        int image_size;
+        int xresolution;
+        int yresolution;
+        int num_colors;
+        int num_important_colors;
+    } __attribute__ ((packed)) info_t;
+
+    BMP(const char * fileName);
+    BMP(const char * fileName, int width, int height, unsigned char * data);
+    ~BMP();
+    void    read(unsigned char * buf);
+    int     getWidth() { return m_info.width; }
+    int     getHeight() { return m_info.height; }
+
+protected:
+    FILE *      m_fp;
+    header_t    m_header;
+    info_t      m_info;
+
+    bool    open(const char * fileName);
+    bool    create(const char * fileName, int width, int height,
+                   unsigned char * data);
+    void    close();
+};

WebcamTracker.cc

@@ -11,6 +11,7 @@
 #include <string.h>                 /* memset() */
 #include <iostream>
 #include "WebcamTracker.h"
+#include "BMP.h"
 using namespace std;
 
 int main(int argc, char * argv[])
@@ -59,7 +60,9 @@ bool WebcamTracker::open(const char * device)
 
 void WebcamTracker::start()
 {
-    setFormat(640, 480);
+    int width = 640;
+    int height = 480;
+    setFormat(width, height);
     requestBuffers(20);
     for (int i = 0; i < m_numbufs; i++)
     {
@@ -67,9 +70,26 @@ void WebcamTracker::start()
         queueBuffer(i);
     }
     beginStreaming();
+
     v4l2_buffer buf;
     dequeueBuffer(&buf);
     endStreaming();
+
+    /* do something with the image referenced by buf */
+    unsigned char * image_data = (unsigned char *) m_buffers[buf.index];
+    unsigned char * bmp_data = new unsigned char[width * height * 3];
+    for (int j = 0; j < height; j++)
+    {
+        for (int k = 0; k < width; k++)
+        {
+            unsigned char y = image_data[(width * j + k) * 2];
+            bmp_data[width * j * 3 + k * 3] = y;
+            bmp_data[width * j * 3 + k * 3 + 1] = y;
+            bmp_data[width * j * 3 + k * 3 + 2] = y;
+        }
+    }
+    BMP bmp("webcam.bmp", width, height, bmp_data);
+    delete bmp_data;
 }
 
 void WebcamTracker::requestBuffers(int num)