When you draw two images, the row stride is still 360*3, but the width
of the drawing area is 720 pixels.
Isn't the expected result something like the following? (n:m means
image n, row m)
1:1 1:2
1:2 1:3
1:3 1:4
........
1:639 1:640
1:640 2:1
2014-07-03 15:57, sunil skrev:
Hey All,
I am trying to draw live images in Gtk::DrawingArea in the
same way as they are shown in monitors at railway stations, airports, metro
etc..
For current tesing purpose I have hardcoded my code.
here it is
Gtkk::Drawing area width=720, height=640.
I have first.pgm and second.pgm images each having 360*640
dimesions.(Yes, i rotated it for testing purpose.)
These images contains one byte per pixel.
1) drawing fine when drwing single image.
I just read the image into *unsigned char* buffer* of size 360*640*3.
i have read it like this
int bufferIndex=0;
int fileIndex=0; //just assume
for (int i=0; i<height; i++)
{
for (int j=0; j<width; j++)
{
//below three lines are for RGB purpose required in
Gdk::Pixbuf
buffer[bufferIndex++] = //File[fileIndex];
buffer[bufferIndex++] = //File[fileIndex];
buffer[bufferIndex++] = //File[fileIndex];
}
}
Gdk::Colorspace colorSpace = Gdk::COLORSPACE_RGB;
Gdk::Colorspace colorSpace = (Gdk::Colorspace)0;
bool has_alpha = false;
int bits_per_sample = 8;
int rowStride = 360*3; // distance between rows in bytes
Glib::RefPtr<Gdk::Pixbuf> pixBuf =
Gdk::Pixbuf::create_from_data((const guint8 *) buffer,
colorSpace, has_alpha, bits_per_sample, 360, 640, rowStride);
Glib::RefPtr<Gdk::GC> gcContext;
pixBuf->render_to_drawable(drawingArea pointer, gcContext, 0,
0, 0 ,
0 , 360, 640, Gdk::RGB_DITHER_MAX, 0, 0);
//It prints the image in the left half of drawing area.
IT IS SAME AS I EXPECTED.
* REAL PROBLEM COMES WHEN I DRAW TWO IMAGES.*
for that purpose I read first.pgm in buffer and after that i read
second.pgm (means total [360*640*3]*2 bytes)
Now i draw it as shown int the code.
Glib::RefPtr<Gdk::GC>gcContext;
Gdk::Colorspace colorSpace = Gdk::COLORSPACE_RGB;
Gdk::Colorspace colorSpace = (Gdk::Colorspace)0;
bool has_alpha = false;
int bits_per_sample = 8;
int rowStride = 360*3; // distance between rows in bytes
Glib::RefPtr<Gdk::Pixbuf> pixBuf = Gdk::Pixbuf::create_from_data((const
guint8 *) buffer,
colorSpace, has_alpha, bits_per_sample, 720, 640, rowStride);
pixBuf->render_to_drawable(drawingarea pointer, gcContext, 0, 0, 0 ,
0 , 720, 640, Gdk::RGB_DITHER_MAX, 0, 0);
Result::
In both half of the Gtk::Drwing area it prints first.pgm image
only???
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