Re: [Image-SIG] Creating a Transparent Image and Placing it Over Another Image

[Wayne Watson]

Digging around hasn't been very successful; however, with your suggestion above to look for images and drawing in Wiki-land may pay off. Drawing on top of an image doesn't seem like it's going to help much if I want the user to move the circle-crosshair with his mouse. In some ways this is kind of standard stuff found in programs like PaintShopPro, and PhotoShop. The ideas are the same as PIL in that layers correspond to a PIL modes, and bands are sub-layers that contain R,B,G, A. In PSP, one piles a transparency on top of another layer. In PIL land it seems like, according to the example, one pastes into the layer. Somehow I doubt that's the way it works. I would think they get stacked on top of one another, so they could slide easily if required by a mouse. It could go either way depending on use. Something that may be instructive on these needs is Grayson's book on Tkinter, which has a few chapters on the web. He provides all the examples, and one chapter of his book is a drawing program that uses rubberband effects, and moving objects on the canvas--maybe even IP work. I think I will shortly fire up the drawing program, after I locate the Pmw toolkit, which he likes to use. As for xpPython, I know little about it. I'm working with a 2000+ line program written by someone else that uses Tkinter. I'm adding new features to it, and  not so sure it's wise to go off onto some other form of Python or toolkits without understanding what I've really got. I had not used Tkinter until 2 months ago, when I began this effort, and only have about 3 months of Python experience. However, I have plenty of programming experience in days of yore. A few weeks ago I bought Core Python and the author has a few pages on it, but doesn't make much of a case for it. He says though, "The best part of all is that wxWidgets use the native GUI on each platform, so your program will have the same loo-and-feel as the other applications on your desktop."  That doesn't send me running for wxPython. Christopher Barker wrote: Wayne Watson wrote: So far I've used Python with Tkinter, and a touch of PIL. I'm pretty bound by Tkinter, since I'm modifying a program that used it quite a bit for the GUI ability rather than analysis of images with IP (image processing). OK, then dig around in the Tk docs and examples you can find. In any case, what I'm suggesting is that you don't need any fancy transparency in PIL -- you simply draw your image onto the screen (probaly add it to the Tk Canvas), then you draw your circle with the cross-hair on top of it, using Tk -- you aren't changing your image, so you can get it back by re-drawing it, or just removing the cross hair. -Chris -- Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) "Less than all cannot satisfy Man." -- William Blake

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