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Getting started with color transparency
For operating with textures two bitmaps are necessary: a source-bitmap
or texture, and a target bitmap or the bitmap on which the texture will
be applied to. For color transparency one third element is necessary:
the transparency color. The color, of course, must belong to the texture
for the merge to take place.
It works like this: the special-effect looks at each
pixel in the texture, and if it founds a match with the transparency color,
just skips that pixel and uses the pixel from the target bitmap instead.
- Setting the transparency color. You
have two choices:
- Select the Pipette-tool from the toolbar and move the mouse to
the bitmap which you'll use as texture, press the ALT-Key and click once with
the right-mouse button. At this point change to the select-tool by
pressing CTRL-Key and right-mouse button, to prevent from changing
mistakingly the transparency color again. Open the Extras-page
if you like to check the color just set.
- Open the Extras-Page in the settings-notebook and enter under
Texture with color transparency the Red, Green, and Blue values of
the color (between 0-255).
- Setting the current texture. Defining a texture
is an easy step. Load any bitmap into LogoArt, mark the object and then select
the Set bitmap as texture"-menu under Extras. That's it. This
texture is valid until you define another in the same fashion, or until
LogoArt ends.
- Setting the target bitmap. This is
even easier: Mark any bitmap.
- Applying color transparency. Make sure the
steps above are done, then click the
Extras->Bitmap effects->Color transparency (Bitmap texture)-
menu. The texture will be applied to the current selected bitmap, taking into
account the transparency color set.
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Texture sample
In this sample we'll show how to apply transparency using two
starting bitmaps. Notice that both input bitmaps (target and texture)
have the same dimensions. By default, the texture is applied again
if it is smaller than the target. Here is the final result:
and the starting bitmaps, target-bitmap and texture:
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We wont go in detail thru the procedure on how these bitmaps were
created. Just a few words to them:
- The target bitmap (WORKSHOP)
was created first, using a rectangle with 250X250 pixels. The rectangle
was filled white. A tif-file of the world was imported and sized about
2/3 of the rectangle, and the words WORK-SHOP in dark-grey were created
using the "Mechanic"-font. All was put on top of the rectangle and a bitmap
generated. Next, the bitmap was converted to grey-tones and a texture
was applied to it. Finally, embossing came in place.
- For the second bitmap a copy of the WORK-SHOP-bitmap was made, and converted
to the background color using the pipette (mark the copy, go with the pipette
under the background color of the first bitmap, and press the CTRL-Key
with the left mouse-button). We took the original vector graphics with the
words LogoArt, made them dark-grey and applied blurring and blend. We
positioned the original logo a bit shifted on the blurred image so that
the shadow-effect is visible and create a bitmap of the whole thing.
- make sure we have a clean drawing area. Click on New
on the upper-left icon if necessary.
- Load now into LogoArt both bitmaps shown above.
- We have not applied any textures yet. We need to set texture and transparency
color first. Mark the bitmap with the word "LogoArt" and select
Extras->Set Bitmap as texture. Here again the result:
- We could get real fancy now. We have applied next a texture
created from a dithered rectangle and "paper.bmp" in "os2/bitmap".
- We have one last step left: to save the new image. Select
Bitmap->Save bitmap file.. to get the file-dialog and enter a
name of your choice for the new bitmap. Of course, you could save in this
manner each bitmap created on the steps before (I do actually). Even more,
I create a copy of the bitmap before applying an effect - there is no
undo for special effects.
If you attempt to save the art-file itself now,
LogoArt will complain if you don't save any modified bitmap explicitely.
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