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65 lines
1.6 KiB
Markdown
65 lines
1.6 KiB
Markdown
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The [_BLEND](_BLEND) statement turns on 32 bit alpha blending for an image or screen mode and is on by default.
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## Syntax
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> [_BLEND](_BLEND) [imageHandle&]
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### Parameters
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* imageHandle& refers to an image in memory. If not specified, the current destination page (See [_DEST](_DEST)) is affected.
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## Description
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* Alpha blending is on by default when loading a .PNG image to a 32-bit surface.
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* Normally it is used to turn blending on after a previous [_DONTBLEND](_DONTBLEND) call.
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* [_BLEND](_BLEND) can only be used on 32-bit surfaces, otherwise it will produce the error [ERROR Codes](ERROR-Codes).
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* **Note: [_DONTBLEND](_DONTBLEND) is faster than the default [_BLEND](_BLEND) unless you really need to use it in 32 bit.**
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* **32 bit screen surface backgrounds (black) have zero [_ALPHA](_ALPHA) so that they are transparent when placed over other surfaces.**
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## Example(s)
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```vb
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SCREEN _NEWIMAGE(640, 480, 32)
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'CLS , _RGB(128, 128, 128) 'change background color for other results
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_DONTBLEND
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bg& = POINT(0, 0)
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PRINT _RED(bg&), _GREEN(bg&), _BLUE(bg&), _ALPHA(bg&)
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LINE (100, 100)-(200, 200), _RGBA32(255, 128, 0, 128), BF
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LINE (440, 100)-(540, 200), _RGBA32(0, 0, 255, 64), BF
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K$ = INPUT$(1)
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_BLEND
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LINE (270, 300)-(370, 400), _RGBA32(255, 128, 0, 128), BF
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m& = POINT(303, 302)
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PRINT _RED(m&), _GREEN(m&), _BLUE(m&), _ALPHA(m&)
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K$ = INPUT$(1)
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LINE (270, 300)-(370, 400), _RGBA32(0, 0, 255, 64), BF
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m& = POINT(303, 302)
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PRINT _RED(m&), _GREEN(m&), _BLUE(m&), _ALPHA(m&)
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```
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```text
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_RGBA(255,128,0,128) onto _RGBA(0,0,255,64)
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results in
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_RGBA(95,48,64,128)
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```
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## See Also
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* [_DONTBLEND](_DONTBLEND), [_BLEND (function)](_BLEND-(function))
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* [Images](Images)
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