Fast 2D Raster Rendering with GUI

[sturlamolden]

On 18 Mar, 17:48, Miki <miki.teb... at gmail.com> wrote:

> Apart from PIL, some other options are:
> 1. Most GUI frameworks (wxPython, PyQT, ...) give you a canvas object
> you can draw on

Yes, but at least on Windows you will get a GDI canvas. GDI is slow.


> 2. A bit of an overkill, but you can use PyOpenGL

OpenGL gives you a fast 'bitblit' for drawing bitmaps to the fram
buffer (much faster than GDI). Here is some C code that does that (8-
bit color depth). Translating to Python is trivial. I prefer not to
use PyOpenGL as it has some unwanted overhead. It is better to use
ctypes.


void bitblt(void *frame, int w, int h)
{
	glViewport(0,0,w,h);
	glClearColor(0.0, 0.0, 0.0, 0.0);
	glClear(GL_COLOR_BUFFER_BIT);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0.0, (GLfloat)w, 0.0, (GLfloat)h);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	glRasterPos2i(0,0);
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
	glDrawPixels(w, h, GL_RGB, GL_UNSIGNED_BYTE_3_3_2, (GLvoid *)frame);
	glFlush();
}