Direct painting on bitmap

Desktop wxRuby
1

Hi, All -

I’ve been getting closer and closer to a raw painting interface (see
‘Inserting
RMagick RVG images in wxRuby’ for my starting point) and now what I’m
working on (yes, I’m getting paid to work today; my kids are 3000 miles
away
so it’s a welcome distraction) is drawing on a MemoryDC associated with
a
bitmap:

    @picture = Bitmap.new( size_x, size_y )
    artist = MemoryDC.new
    artist.select_object @picture
    artist.set_background_mode SOLID
    artist.flood_fill( 160, 200, Colour.new( 240, 0, 0, 255 ) )

… and later:

    paint_bitmap( @picture, client_size.x, client_size.y )

using the definition (part of my Window sub-class):

def paint_bitmap bitmap, width, height
    bitmap = make_dummy if bitmap == nil # dummies for non-existant

images (like cpu1 if single-thread)
rescaled_bitmap = Bitmap.from_image(
bitmap.convert_to_image.rescale( width, height ), -1 )
rescaled_bitmap.save_file( @fname, BITMAP_TYPE_XPM )
paint do | renderer |
renderer.draw_bitmap( rescaled_bitmap, 0, 0, false )
end
@sized = false
end

What appears to be happening is that my bitmaps are not taking over from
the
original contents of the memory arrays, because what I see being
rendered
appears to be garbage pages from the screen buffer. If I change
something in
my GUI (like pressing a button, which changes its color to yellow), I
see
smears of yellow showing up in my bitmaps and getting rendered in my
GUI.

The Bitmap#draw method referenced in the DC and MemoryDC docs appears to
have gone bye-bye in 2.0, so I’m using the direct instantiation menthod.
I
finally got my copy of Smart and Hock and it says something about
select_object not working if the bitmap is unpopulated, so my next try
is to
pull up a base bitmap from a file instead of creating one from new.

Thanks in advance! :smiley:

2

On Thu, Nov 25, 2010 at 2:57 PM, Don W. [email protected] wrote:
[snip]

using the definition (part of my Window sub-class):
@sized = false
end

[snip]

Bitmap#load_file is also gone, but Bitmap.new has a file option. Never
rely
on a first-release API to be as documented. :wink:

Changing make_dummy to load a file got rid of the uninitialized bitmaps,
but
I still can’t paint anything on them. The above code should leave me
with a
screaming red bitmap, but all I get is the white from my blank.png.

3

On Thu, Nov 25, 2010 at 3:19 PM, Don W. [email protected] wrote:
[snip]

    artist.flood_fill( 160, 200, Colour.new( 240, 0, 0, 255 ) )

Never mind. I just re-read the flood_fill docs and discovered that the
Colour in the command is the BOUNDARY color, not the painting color.

You can stop laughing now, hope you enjoyed. :smiley: