Python PIL Image.tostring()
我是 Python 和 PIL 新手。我正在尝试遵循代码示例,了解如何通过 PIL 将图像加载到 Python,然后使用 openGL 绘制其像素。以下是一些代码行:
from Image import *
im = open("gloves200.bmp")
pBits = im.convert('RGBA').tostring()
.....
glDrawPixels(200, 200, GL_RGBA, GL_UNSIGNED_BYTE, pBits)
这将在画布上绘制 200 x 200 的像素块。然而,它不是预期的图像——它看起来像是从随机存储器中绘制像素。即使我尝试绘制完全不同的图像,我也会得到相同的图案,这一事实支持了随机记忆假设。有人可以帮助我吗?我在 Windows XP 上使用 Python 2.7 以及 2.7 版本的 pyopenGL 和 PIL。
I'm new to Python and PIL. I am trying to follow code samples on how to load an image into to Python through PIL and then draw its pixels using openGL. Here are some line of the code:
from Image import *
im = open("gloves200.bmp")
pBits = im.convert('RGBA').tostring()
.....
glDrawPixels(200, 200, GL_RGBA, GL_UNSIGNED_BYTE, pBits)
This will draw a 200 x 200 patch of pixels on the canvas. However, it is not the intended image-- it looks like it is drawing pixels from random memory. The random memory hypothesis is supported by the fact that I get the same pattern even when I attempt to draw entirely different images.Can someone help me? I'm using Python 2.7 and the 2.7 version of pyopenGL and PIL on Windows XP.
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我想你很接近。尝试:
首先必须将图像转换为 RGBA 模式,以便 RGBA rawmode 打包程序可用(请参阅 Pack.c 在 libimaging 中)。您可以检查
len(pBits) == im.size[0]*im.size[1]*4
,对于您的 glove200 图像,它是 200x200x4 = 160,000 字节。I think you were close. Try:
The image first has to be converted to RGBA mode in order for the RGBA rawmode packer to be available (see Pack.c in libimaging). You can check that
len(pBits) == im.size[0]*im.size[1]*4
, which is 200x200x4 = 160,000 bytes for your gloves200 image.您是否尝试过直接使用 tostring 函数内部的转换?
或者使用兼容版本:
Have you tried using the conversion inside the tostring function directly?
Alternatively use compatibility version:
谢谢你的帮助。感谢 mikebabcock 更新了 Web 上的示例代码。感谢 eryksun 提供的代码片段——我在我的代码中使用了它。
我确实发现了我的错误,这是Python新手的错误。哎哟。我在模块中任何函数的范围之外声明了一些变量,并天真地认为我正在函数内修改它们的值。当然,这是行不通的,所以我的 glDrawPixels 调用实际上是在绘制随机内存。
Thank you for the help. Thanks to mikebabcock for updating the sample code on the Web. Thanks to eryksun for the code snippet-- I used it in my code.
I did find my error and it was Python newb mistake. Ouch. I declared some variables outside the scope of any function in the module and naively thought I was modifying their values inside a function. Of course, that doesn't work and so my glDrawPixels call was in fact drawing random memory.