Canvas rectangle filling

Suresh Kumar suresh_vsamy at rediffmail.com
Sat Jun 14 19:27:20 CEST 2003


Thanks Daniel,
     Thanks for your timely help. I got it. I created a "xmb" file and filled my rectangle. Still i have some problems that i would like to bring your attention. 
       
     i have created a stack of rectangles all of same size, say 200 pixel wide and 100 pixel height. Each rectangle is given some color and stipple to "gray75". Then i placed some samll rectangles of some size, say 50 pixel wide and 50 pixel height , on each bigger rectangle and assigened some color and stipple to "lines.xbm". I got the o/p such that the smaller rectangles are filled with "line.xbm". But the samller rectangles are looking so transparent. It means, all areas other than ocupied by "line.xbm" is filled with bigger rectangle's color. My requirement is, all smaller rectangles should be filled with "lines.xbm" and they should not be transparent. 

   My coding is as follows:
   
self.canvas.create_rectangle ( 100,100,200,200, fill='blue', stipple='gray75)
self.canvas.create_rectangle( 100,200,200,300,fill='red', stipple="gray50")
self.canvas.create_rectangle((100,300,200,400, fill='black', stipple="gray25")
######### Small rectagnles
self.canvas.create_rectangle(100,150,150,200, fill='black', stipple="@line.xbm")
self.canvas.create_rectangle(100,250,150,300, fill='black', stipple="@line.xbm")

    I attached my required o/p in this mail as "sample.gif". Have a   
look and give me your suggestion and me let me how to avoid transparancy.

With regeards,
V.Suresh Kumar.
  

On Thu, 12 Jun 2003 Abel Daniel wrote :
>Suresh  Kumar wrote:
> > Hi,
> > Iam using python/tkinter/pmw in windows.
> > Most of graphics languages provides facility to fill the rectangcle with
> > horizantal/vertical lines. I know that in tkinter we can fill the canvas
> > rectangle's interior using "stipple". But my customer is expecting the
> > rectangles to be filled with  diagnal/vertical/horizantal lines. Is
> > there any direct way is available in tkinter/Pmw to fill the rectangle with
> > lines?
> > or i have to use "create_line" command explicitly?
>Well, creating the lines invidually is an option, but i think it's a
>rather poor one. You would have to figure out the endpoints of each
>line, which might work for rectangles, but will get almost impossible
>for circles, or arcs.
>(Not to mention that you would be creating a lot of lines, which i guess
>would impact performance.)
>
>I think the best idea would be to use stipple with custom bitmaps. For
>example the following xbm file will create diagonal lines:
>----8<----
>/* Created with The GIMP */
>#define lines_width 16
>#define lines_height 16
>static unsigned char lines_bits[] = {
>    0x11, 0x11, 0x22, 0x22, 0x44, 0x44, 0x88, 0x88, 0x11, 0x11, 0x22, 0x22,
>    0x44, 0x44, 0x88, 0x88, 0x11, 0x11, 0x22, 0x22, 0x44, 0x44, 0x88, 0x88,
>    0x11, 0x11, 0x22, 0x22, 0x44, 0x44, 0x88, 0x88 };
>----8<-----
>Copy-paste this into a file, call it 'lines.xbm', and use it like:
>canvas.create_rectangle(100,100,150,150, stipple='@lines.xbm', fill='black')
>
>There might be two problems:
>1) path to the xbm files. If you put your xbm files somewhere else than
>the current directory, I think you will have to use the full path, like:
>... stipple='@/path/to/file.xbm' ...
>Which might complicate the matters as you have to keep track of where
>your xbm files are, and use the appropriate path.
>
>2) creating the xbm files themselves. If you only need some options like
>'diagonal lines, close the each other' or 'vertical lines, far apart'
>you could create some xbm files, and only provide those. (Essentially
>hardcoding thos patterns.) If you need more flexibility, like 'lines at
>60 degrees angle, 2 pixels wide and 7 pixels apart' you will have to
>generate xbm files on the fly. A way of pipeing the xbm data would come
>handy in this case, but I don't know if such exists. You might have to
>save the generated xbm data to be able to pass the filename to tkinter.
>I think generating the xbm files on the fly will be pretty easy, as they
>are simply black&white bitmaps.
>
>According to
>http://www.pythonware.com/library/tkinter/introduction/x2861-options.htm
>which is describing the options of arc object:
>"As of Tk 8.0p2, the stipple option is ignored on the Windows platform.
>To draw stippled pieslices or chords, you have to create corresponding
>polygons."
>
>But I think that doesn't affect other objects. (I didn't test on Windows)
>
>Abel Daniel
>
>_______________________________________________
>Tutor maillist  -  Tutor at python.org
>http://mail.python.org/mailman/listinfo/tutor
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