| from test_support import verbose |
| |
| import imgfile |
| |
| |
| def main(): |
| |
| getimage('test.rgb') |
| getimage('greytest.rgb') |
| |
| |
| def getimage(name): |
| """return a tuple consisting of |
| image (in 'imgfile' format) width, height, size |
| """ |
| |
| import sys |
| import os |
| import string |
| |
| outputfile = '/tmp/deleteme' |
| |
| # try opening the name directly |
| try: |
| # This function returns a tuple (x, y, z) where x and y are the size of |
| # the image in pixels and z is the number of bytes per pixel. Only |
| # 3 byte RGB pixels and 1 byte greyscale pixels are supported. |
| sizes = imgfile.getsizes(name) |
| except imgfile.error: |
| # get a more qualified path component of the script... |
| if __name__ == '__main__': |
| ourname = sys.argv[0] |
| else: # ...or the full path of the module |
| ourname = sys.modules[__name__].__file__ |
| |
| parts = string.splitfields(ourname, os.sep) |
| parts[-1] = name |
| name = string.joinfields(parts, os.sep) |
| sizes = imgfile.getsizes(name) |
| if verbose: |
| print 'Opening test image: %s, sizes: %s' % (name, str(sizes)) |
| # This function reads and decodes the image on the specified file, |
| # and returns it as a python string. The string has either 1 byte |
| # greyscale pixels or 4 byte RGBA pixels. The bottom left pixel |
| # is the first in the string. This format is suitable to pass |
| # to gl.lrectwrite, for instance. |
| image = imgfile.read(name) |
| |
| # This function writes the RGB or greyscale data in data to |
| # image file file. x and y give the size of the image, z is |
| # 1 for 1 byte greyscale images or 3 for RGB images (which |
| # are stored as 4 byte values of which only the lower three |
| # bytes are used). These are the formats returned by gl.lrectread. |
| if verbose: |
| print 'Writing output file' |
| imgfile.write (outputfile, image, sizes[0], sizes[1], sizes[2]) |
| |
| |
| if verbose: |
| print 'Opening scaled test image: %s, sizes: %s' % (name, str(sizes)) |
| # This function is identical to read but it returns an image that |
| # is scaled to the given x and y sizes. If the filter and blur |
| # parameters are omitted scaling is done by simply dropping |
| # or duplicating pixels, so the result will be less than perfect, |
| # especially for computer-generated images. Alternatively, |
| # you can specify a filter to use to smoothen the image after |
| # scaling. The filter forms supported are 'impulse', 'box', |
| # 'triangle', 'quadratic' and 'gaussian'. If a filter is |
| # specified blur is an optional parameter specifying the |
| # blurriness of the filter. It defaults to 1.0. readscaled |
| # makes no attempt to keep the aspect ratio correct, so that |
| # is the users' responsibility. |
| if verbose: |
| print 'Filtering with "impulse"' |
| simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'impulse', 2.0) |
| |
| # This function sets a global flag which defines whether the |
| # scan lines of the image are read or written from bottom to |
| # top (flag is zero, compatible with SGI GL) or from top to |
| # bottom(flag is one, compatible with X). The default is zero. |
| if verbose: |
| print 'Switching to X compatibility' |
| imgfile.ttob (1) |
| |
| if verbose: |
| print 'Filtering with "triangle"' |
| simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'triangle', 3.0) |
| if verbose: |
| print 'Switching back to SGI compatibility' |
| imgfile.ttob (0) |
| |
| if verbose: print 'Filtering with "quadratic"' |
| simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'quadratic') |
| if verbose: print 'Filtering with "gaussian"' |
| simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'gaussian', 1.0) |
| |
| if verbose: |
| print 'Writing output file' |
| imgfile.write (outputfile, simage, sizes[0]/2, sizes[1]/2, sizes[2]) |
| |
| os.unlink(outputfile) |
| |
| main() |