[pygtk] Re: GdkGC GdkColor GtkDrawingArea

[Philip Porter]

> Could someone please help me with this problem. I would like to have a
> better understanding of how to use GdkGC's. Here is some example code to
> explain what I would like to be able to do:
> 
> 
> def on_button1_clicked(widget, mainObj):
>     
>     GdkWindow = widget.get_parent_window()

>     gc = GdkWindow.new_gc()
> 
>     for x in range(1,64):
>         for y in range(1,48):
> 
>             color =  GdkColor(x * 100, y * 100, 0)
>             gc.foreground = color
>             
>             mainObj.drawingarea1.draw_point(gc, x, y)
> 
> 
> This code does not work the way I would expect, the color used is
> allways the default foreground of the theme I have installed. 
> 
> I have tried to find an example of someone changing the color in a GdkGC
> and drawing on a DrawingArea. The code I have seen only uses the default
> colors.
> 
> Thanks allot,
> 
> Phil
> .
> 

Well this is what I came up with, I'll put it here for anyone else.

Thanks to François Pinard's post
http://www.daa.com.au/pipermail/pygtk/2000-August/000247.html

and acano@systec.com post
http://www.daa.com.au/pipermail/pygtk/2000-August/000219.html


def on_button1_clicked(widget, mainObj):

    xmax = 64.
    ymax = 48.
    
    zoom = 16
    bdr = 1
    
    area = mainObj.drawingarea1.get_window()
    pixmap = create_pixmap(area, area.width, area.height)
    
    gc = area.new_gc()
    cm = mainObj.drawingarea1.get_style().colormap
    
    black_gc = mainObj.drawingarea1.get_style().black_gc
    white_gc = mainObj.drawingarea1.get_style().white_gc
    
    x = 0
    y = 0
     
    FILL = 1
    NOFILL = 0

    
    for x in range(0, xmax):
        for y in range(0, ymax):
            
            r = (y / ymax) * 65535
            g = (x / xmax) * 65535
            b  = (r + g) / 2
            
            color = cm.alloc(r, g, b)
            
            gc.foreground = color
            
            #draw_arc(pixmap, gc, FILL, x * zoom, y * zoom  ,
zoom-bdr  , zoom-bdr , 90 * 64, 360 * 64)
            draw_rectangle(pixmap, gc, FILL, x * zoom + 1, y * zoom,
zoom - bdr, zoom - bdr)
            #draw_point(pixmap, white_gc, x * zoom + (zoom/2), y * zoom
+ (zoom/2))
            
    draw_pixmap(area, gc, pixmap, 0, 0, 0, 0, (xmax) * zoom, (ymax) *
zoom)


Phil
.