16 messages in com.googlegroups.pyglet-usersRe: setting gamma| From | Sent On | Attachments |
|---|---|---|
| Martin Spacek | Dec 29, 2007 2:20 am | |
| Alex Holkner | Dec 29, 2007 3:55 pm | |
| Andrew Straw | Dec 29, 2007 9:06 pm | |
| Martin Spacek | Dec 29, 2007 11:48 pm | |
| Alex Holkner | Dec 30, 2007 1:09 am | |
| Martin Spacek | Jan 6, 2008 9:50 pm |  .py |
| Alex Holkner | Jan 7, 2008 1:14 am | |
| Martin Spacek | Jan 7, 2008 4:05 am | .py |
| Andrew Straw | Jan 7, 2008 10:51 am | |
| Alex Holkner | Jan 7, 2008 1:59 pm | |
| Andrew Straw | Jan 7, 2008 9:10 pm | |
| Martin Spacek | Jan 7, 2008 9:34 pm | |
| Martin Spacek | Jan 7, 2008 9:47 pm | |
| Alex Holkner | Jan 7, 2008 11:01 pm | |
| Jon | Feb 2, 2008 8:26 am | |
| PhilipBober | Feb 2, 2008 11:16 pm |
| Subject: | Re: setting gamma | |
|---|---|---|
| From: | Martin Spacek (pyg...@mspacek.mm.st) | |
| Date: | Jan 7, 2008 4:05:43 am | |
| List: | com.googlegroups.pyglet-users | |
| Attachments: | ||
Alex Holkner wrote:
The buffer needs to be 3 arrays of 256 words (you have only allocated the same number of bytes). So:
buf = ((c_uint16) * 256) * 3)()
where buf[0] is the red ramp, buf[1] is the green ramp, etc.
[GS]etDeviceGammaRamp needs a graphics device context, not an OpenGL context. So:
ret = windll.gdi32.GetDeviceGammaRamp(win._dc, buf) ret = windll.gdi32.SetDeviceGammaRamp(win._dc, buf)
(the byref is unnecessary; arrays are always passed as pointers in C).
Alex.
Ah, thanks. I just figured both of those out the hard way. (I thought words were 8bit for some reason). It works great now. Here's the demo. I'm using numpy to create the gamma ramps.
Not sure if/how you want to incorporate this into pyglet. This is only the win32 call, linux and osx would have to be figured out too. Maybe a pyglet.window.Window.set_gamma(r, g, b) method, where you provide the 3 gamma values and it generates and sets the ramps for you? Or maybe make it a Screen method since setting gamma affects the whole screen?
Martin
"""Demo of how to set screen gamma in win32 using ctypes for a pyglet device context"""
from __future__ import division
import pyglet.window import numpy as np from ctypes import windll import time
gamma = 2.2
def invramp(gamma): """Inverted gamma ramp""" ramp = np.arange(256, dtype=np.uint16) / 255 # normalized linear ramp ramp = np.power(ramp, 1 / gamma) * 255 # unnormalized inverted gamma ramp return np.uint16(np.round(ramp)) # convert back to nearest ints
win = pyglet.window.Window() origramps = np.empty((3, 256), dtype=np.uint16) # init R, G, and B ramps
# try and get gamma ramp success = windll.gdi32.GetDeviceGammaRamp(win._dc, origramps.ctypes) if not success: raise AssertionError, 'GetDeviceGammaRamp failed'
ramp = invramp(gamma=gamma) ramps = np.asarray([ramp]*3) # identically inverted R, G, and B ramps ramps.byteswap(True) # seems CPU and GPU have different endianness?
# try and set gamma ramp success = windll.gdi32.SetDeviceGammaRamp(win._dc, ramps.ctypes) if not success: raise AssertionError, 'SetDeviceGammaRamp failed'
time.sleep(3) # marvel at gamma corrected screen
# reset to original gamma success = windll.gdi32.SetDeviceGammaRamp(win._dc, origramps.ctypes) if not success: raise AssertionError, 'SetDeviceGammaRamp failed'