Re: Setting the corner color in rotated PIL images
Fredrik Lundh [EMAIL PROTECTED] wrote in news:[EMAIL PROTECTED]: rzed wrote: I'm using PIL to generate some images which may be rotated at the user's option. When they are rotated, the original image is cropped in the new image (which is fine), and the corners are black (which is not, in this case). I can't find any documented way to change the default fill color (if that's what it is) for the corners, and PIL also doesn't seem to support a flood fill. I have created a flood fill in Python, which works but which markedly slows image generation. Can anyone suggest a better way to set the color of the corners? if you're doing this on RGB images, the quickest way to do this is: def rotate(image, angle, color): bg = Image.new(RGB, image.size, color) im = image.convert(RGBA).rotate(angle) bg.paste(im, im) return bg here's a more general solution: def rotate(image, angle, color, filter=Image.NEAREST): if image.mode == P or filter == Image.NEAREST: matte = Image.new(1, image.size, 1) # mask else: matte = Image.new(L, image.size, 255) # true matte bg = Image.new(image.mode, image.size, color) bg.paste( image.rotate(angle, filter), matte.rotate(angle, filter) ) return bg /F Fredrik: Thank you for the reply. It just showed up on my server, and, of course, it works perfectly. -- rzed -- http://mail.python.org/mailman/listinfo/python-list
Re: Setting the corner color in rotated PIL images
What do you mean 'is required'? I tend to think that getting ahead with a job is what is required. I don't sneer at work-arounds if they save time. Frederic A somewhat craftier solution, if still pretty hackish, would be to go through your image pixel by pixel, look what color each one is (color = image.getpixel (here)) and change the ones with the wrong color (if color == wrong_color: putpixel (here, right_color)). If the color of the corners does not occur inside your picture, you can go throught the entire image. Else you'd have to stop changing colors at the first occurrence of a pixel that does not have the wrong color, coming inward from each of the lateral edges. (Code below (untested)). If you have elements in your picture that not only have the same color as the corners, but also run into them, then you might have to refine your code further in order for the inner loop not stray into the image. # Left edge for y in range (image.size [1]): for x in range (image.size [0]): color = image.getpixel ((x,y)) if color != WRONG_COLOR: break image.putpixel ((x,y), RIGHT_COLOR) # Right edge for y in range (image.size [1]): for x in range (image.size [0]-1), -1, -1): color = image.getpixel ((x,y)) if color != WRONG_COLOR: break image.putpixel ((x,y), RIGHT_COLOR) - Original Message - From: rzed [EMAIL PROTECTED] Newsgroups: comp.lang.python To: python-list@python.org Sent: Tuesday, May 03, 2005 8:13 PM Subject: Re: Setting the corner color in rotated PIL images Anthra Norell [EMAIL PROTECTED] wrote in news:[EMAIL PROTECTED]: [in response to: I'm using PIL to generate some images which may be rotated at the user's option. When they are rotated, the original image is cropped in the new image (which is fine), and the corners are black (which is not, in this case). I can't find any documented way to change the default fill color (if that's what it is) for the corners, and PIL also doesn't seem to support a flood fill. I have created a flood fill in Python, which works but which markedly slows image generation.] I just had the same problem the other day. I solved it by starting out with an image large enough to retain enough white area following the rotation. Well, that's a workaround I could try, but I'm half-hearted about it. I don't like to think that it's *required*. Another possible solution is to make the outer portion black, so the rotation seems to do the right things, but in the cases I'm dealing with, that's either out or more trouble than it's worth. I can haul the rotated images into a paint program and manually touch up the corners, too, but I don't like to have to do that either. It seems strange that there wouldn't be some way to change the black to another color, or (maybe just as good) to transparent. PIL is so useful that it strikes me as an aberrant oversight. More likely, there *is* a better way, but I just don't know it and can't find it in the docs. -- rzed -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Setting the corner color in rotated PIL images
[Following up] - Original Message - From: rzed [EMAIL PROTECTED] Newsgroups: comp.lang.python To: python-list@python.org Sent: Sunday, May 01, 2005 1:17 PM Subject: Setting the corner color in rotated PIL images I'm using PIL to generate some images which may be rotated at the user's option. When they are rotated, the original image is cropped in the new image (which is fine), and the corners are black (which is not, in this case). I can't find any documented way to change the default fill color (if that's what it is) for the corners, and PIL also doesn't seem to support a flood fill. I have created a flood fill in Python, which works but which markedly slows image generation. Anthra Norell [EMAIL PROTECTED] wrote in news:[EMAIL PROTECTED]: I just had the same problem the other day. I solved it by starting out with an image large enough to retain enough white area following the rotation. Frederic I found another method that doesn't require the larger size and cropping :) but does require two copies of the original image :( (sort of). I copy the image and rotate the copy, then I create an all-white image of the same size as the original and rotate it by the same amount. Then I use ImageChops composite() to combine the rotated copy, the original copy, and the black-and-white version (parameters in that order). The black corners of the b/w version serve as a mask to paste the original corners onto the copy. It still seems like a lot of trouble to go to, but I don't think there is a ready solution otherwise. I think there's a C-code memset of all zeroes that underlies the black corners thing, and that's not likely to change. -- rzed -- http://mail.python.org/mailman/listinfo/python-list
Re: Setting the corner color in rotated PIL images
rzed wrote: I'm using PIL to generate some images which may be rotated at the user's option. When they are rotated, the original image is cropped in the new image (which is fine), and the corners are black (which is not, in this case). I can't find any documented way to change the default fill color (if that's what it is) for the corners, and PIL also doesn't seem to support a flood fill. I have created a flood fill in Python, which works but which markedly slows image generation. Can anyone suggest a better way to set the color of the corners? if you're doing this on RGB images, the quickest way to do this is: def rotate(image, angle, color): bg = Image.new(RGB, image.size, color) im = image.convert(RGBA).rotate(angle) bg.paste(im, im) return bg here's a more general solution: def rotate(image, angle, color, filter=Image.NEAREST): if image.mode == P or filter == Image.NEAREST: matte = Image.new(1, image.size, 1) # mask else: matte = Image.new(L, image.size, 255) # true matte bg = Image.new(image.mode, image.size, color) bg.paste( image.rotate(angle, filter), matte.rotate(angle, filter) ) return bg /F -- http://mail.python.org/mailman/listinfo/python-list
Re: Setting the corner color in rotated PIL images
Anthra Norell [EMAIL PROTECTED] wrote in news:[EMAIL PROTECTED]: What do you mean 'is required'? I tend to think that getting ahead with a job is what is required. I don't sneer at work-arounds if they save time. Frederic A somewhat craftier solution, if still pretty hackish, would be to go through your image pixel by pixel, look what color each one is (color = image.getpixel (here)) and change the ones with the wrong color (if color == wrong_color: putpixel (here, right_color)). If the color of the corners does not occur inside your picture, you can go throught the entire image. Else you'd have to stop changing colors at the first occurrence of a pixel that does not have the wrong color, coming inward from each of the lateral edges. (Code below (untested)). If you have elements in your picture that not only have the same color as the corners, but also run into them, then you might have to refine your code further in order for the inner loop not stray into the image. [Code snipped] Yes, that is essentially similar to the slow flood-fill approach I used initially. I did in fact make use of your previous suggestion, which works but requires oversizing the image, calculating the crop rectangle and so on -- not overly difficult, just annoying -- and I also use another approach (outlined in another message) that involves pasting a rotated copy of the image back onto the original under control of a mask. It depends on what I want to see in the corners, essentially. And, having coded the workarounds, I get on with the process without worrying about it. But ... it would be nice if I could specify a default solid color to replace the black in the corners, and have the rotation take place in one operation without resizing and recalculating and duplicating images and all. Somewhere down in the C code, the corner color is being set to black. I wouldn't think it would be terribly hard at that stage to set those bytes to other values instead, and exposing that color through PIL's interface. But I suppose it's more trouble than it's worth for Fredrik, or nobody else has been bothered by it, or by the lack of a flood-fill function. To me, these are uncharacteristically odd omissions from PIL. -- rzed -- http://mail.python.org/mailman/listinfo/python-list
Re: Setting the corner color in rotated PIL images
I just had the same problem the other day. I solved it by starting out with an image large enough to retain enough white area following the rotation. Frederic - Original Message - From: rzed [EMAIL PROTECTED] Newsgroups: comp.lang.python To: python-list@python.org Sent: Sunday, May 01, 2005 1:17 PM Subject: Setting the corner color in rotated PIL images I'm using PIL to generate some images which may be rotated at the user's option. When they are rotated, the original image is cropped in the new image (which is fine), and the corners are black (which is not, in this case). I can't find any documented way to change the default fill color (if that's what it is) for the corners, and PIL also doesn't seem to support a flood fill. I have created a flood fill in Python, which works but which markedly slows image generation. Can anyone suggest a better way to set the color of the corners? All I really need in this case is that they be a solid color, the same color they were before being rotated. -- rzed -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Setting the corner color in rotated PIL images
Anthra Norell [EMAIL PROTECTED] wrote in news:[EMAIL PROTECTED]: [in response to: I'm using PIL to generate some images which may be rotated at the user's option. When they are rotated, the original image is cropped in the new image (which is fine), and the corners are black (which is not, in this case). I can't find any documented way to change the default fill color (if that's what it is) for the corners, and PIL also doesn't seem to support a flood fill. I have created a flood fill in Python, which works but which markedly slows image generation.] I just had the same problem the other day. I solved it by starting out with an image large enough to retain enough white area following the rotation. Well, that's a workaround I could try, but I'm half-hearted about it. I don't like to think that it's *required*. Another possible solution is to make the outer portion black, so the rotation seems to do the right things, but in the cases I'm dealing with, that's either out or more trouble than it's worth. I can haul the rotated images into a paint program and manually touch up the corners, too, but I don't like to have to do that either. It seems strange that there wouldn't be some way to change the black to another color, or (maybe just as good) to transparent. PIL is so useful that it strikes me as an aberrant oversight. More likely, there *is* a better way, but I just don't know it and can't find it in the docs. -- rzed -- http://mail.python.org/mailman/listinfo/python-list
