PIL\Tkinter and Transparencies, Rubber Lines, and Dragging Image Objects
Basically, I'd like to know how one (broadly, e.g., references in Win-land) does IP (image processing) and drawing techniques such as rubber lines, and dragging image objects across the canvas. I know there are some pretty powerful toolkits out there, but I'd like to limit this to PIL and Tkinter. If it can't be done with them, then I'll consider other possibilities. As a starter, on the topic of transparencies, consider this program that I pulled off the web and was posted in 1999. It purports to illustrate how one might produce a transparency. #!/usr/bin/python # see http://mail.python.org/pipermail/python-list/1999-May/003388.html from Tkinter import * import Image, ImageTk import tkFileDialog class Transparency: def __init__(self, parent): self.canvas = Canvas(parent, bg='green') self.canvas.pack() b = Button(parent, command=self.open, text=Select graphics file) b.pack() def open(self): self.canvas.delete(ALL) filename = tkFileDialog.askopenfilename() if filename != '': im = Image.open(filename) if im.mode != RGBA: im = Image.open(filename).convert(RGBA) source = im.split() R, G, B, A = 0, 1, 2, 3 mask = im.point(lambda i: i 0 and 255) # use black as transparent source[A].paste(mask) im = Image.merge(im.mode, source) # build a new multiband image self.graphic = ImageTk.PhotoImage(image=im) self.canvas.create_image(100, 100, image=self.graphic) if __name__ == __main__: root = Tk() test = Transparency(root) root.mainloop() It colors the canvas green, and produces a black background. An image is merged with the background. I tried out the program. It executes, but I do not see where the transparency is apparent. I used a gif with a picture of a telescope on a white background, and the result is what I would see if I pasted the telescope and white background onto the green canvas. If there's something missing in my observation, I'd like to know what it is. To further explore drawing graphics, what roughly is the capability of Tkinter or PIL to allow one to place a transparent layer (mode, I guess in PIL may be roughly equivalent to a layer in tools like Photoshop) on top of an image and then move the transparency around over the image with a mouse? -- W. eWatson (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time) Obz Site: 39° 15' 7 N, 121° 2' 32 W, 2700 feet Web Page: www.speckledwithstars.net/ -- http://mail.python.org/mailman/listinfo/python-list
Re: PIL\Tkinter and Transparencies, Rubber Lines, and Dragging Image Objects
W. eWatson wrote: Basically, I'd like to know how one (broadly, e.g., references in Win-land) does IP (image processing) and drawing techniques such as rubber lines, and dragging image objects across the canvas. I know there are some pretty powerful toolkits out there, but I'd like to limit this to PIL and Tkinter. If it can't be done with them, then I'll consider other possibilities. As a starter, on the topic of transparencies, consider this program that I pulled off the web and was posted in 1999. It purports to illustrate how one might produce a transparency. OK, maybe I'm dumb but: #!/usr/bin/python # see http://mail.python.org/pipermail/python-list/1999-May/003388.html from Tkinter import * import Image, ImageTk import tkFileDialog class Transparency: def __init__(self, parent): self.canvas = Canvas(parent, bg='green') self.canvas.pack() b = Button(parent, command=self.open, text=Select graphics file) b.pack() def open(self): self.canvas.delete(ALL) filename = tkFileDialog.askopenfilename() if filename != '': im = Image.open(filename) if im.mode != RGBA: im = Image.open(filename).convert(RGBA) source = im.split() R, G, B, A = 0, 1, 2, 3 mask = im.point(lambda i: i 0 and 255) # use black as transparent source[A].paste(mask) im = Image.merge(im.mode, source) # build a new multiband image self.graphic = ImageTk.PhotoImage(image=im) self.canvas.create_image(100, 100, image=self.graphic) if __name__ == __main__: root = Tk() test = Transparency(root) root.mainloop() It colors the canvas green, and produces a black background. An image is merged with the background. I tried out the program. It executes, but I do not see where the transparency is apparent. I used a gif with a picture of a telescope on a white background, and the result is what I would see if I pasted the telescope and white background onto the green canvas. I have neither PIL, nor the image you're using so I can just guess. But if you want to use a white background, maybe you should use a mask defined with: mask = im.point(lambda i: 255 if i = 255 else 0) (if I understood the mask construction correctly...). HTH - Eric - -- http://mail.python.org/mailman/listinfo/python-list
Re: PIL\Tkinter and Transparencies, Rubber Lines, and Dragging Image Objects
You got it. That lamda did look a little odd. The white background is opaque and the telescope is seen as green. The program will ask for a file. I didn't write the code. Eric Brunel wrote: W. eWatson wrote: Basically, I'd like to know how one (broadly, e.g., references in Win-land) does IP (image processing) and drawing techniques such as rubber lines, and dragging image objects across the canvas. I know there are some pretty powerful toolkits out there, but I'd like to limit this to PIL and Tkinter. If it can't be done with them, then I'll consider other possibilities. As a starter, on the topic of transparencies, consider this program that I pulled off the web and was posted in 1999. It purports to illustrate how one might produce a transparency. OK, maybe I'm dumb but: #!/usr/bin/python # see http://mail.python.org/pipermail/python-list/1999-May/003388.html from Tkinter import * import Image, ImageTk ... HTH - Eric - -- W. eWatson (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time) Obz Site: 39° 15' 7 N, 121° 2' 32 W, 2700 feet Web Page: www.speckledwithstars.net/ -- http://mail.python.org/mailman/listinfo/python-list
