// Add half a pixel tolerance to sprite size, since we later on compare // against it in resize(). And view transformations will almost never yield // the same data bits when transforming to device coordinates
maEffectiveSpriteSizePixel += ::basegfx::B2DSize(0.5, 0.5);
// extract linear part of canvas view transformation // (linear means: without translational components). The // only translation that is imposed at the view transform // is the local content pixel offset.
// We can apply that directly here, no need to call // aLinearTransform.translate(), since, as said above, the // last column of aLinearTransform is assumed [0 0 1]
::basegfx::B2DHomMatrix aLinearTransform( mpViewLayer->getTransformation() );
aLinearTransform.set( 0, 2, maContentPixelOffset.getWidth() );
aLinearTransform.set( 1, 2, maContentPixelOffset.getHeight() );
// apply linear part of canvas view transformation to sprite canvas
pContentCanvas->setTransformation( aLinearTransform );
return pContentCanvas;
}
void AnimatedSprite::resize( const ::basegfx::B2DSize& rSpriteSizePixel )
{ // Enlarge or reduce the sprite size, if necessary. This // method employs a strategy similar to container, when // allocating memory: size is doubled or halved every time // the limit is reached. This makes for amortized constant // time in runtime complexity. Note that we take exact // powers of two here, since several HW-accelerated canvas // implementations are limited to such sprite sizes // (otherwise, those implementations would internally // round up, too, wasting precious mem).
::basegfx::B2DSize aNewSize( maEffectiveSpriteSizePixel ); bool bNeedResize( false );
if( rSpriteSizePixel.getHeight() > maEffectiveSpriteSizePixel.getHeight() ||
rSpriteSizePixel.getHeight() < 0.5*maEffectiveSpriteSizePixel.getHeight() )
{ // enlarge or shrink height, by doubling it
aNewSize.setHeight( ::canvas::tools::nextPow2( ::basegfx::fround(rSpriteSizePixel.getHeight()) ) );
bNeedResize = true;
}
if( !bNeedResize ) return;
// as the old sprite might have already been altered // (and therefore been placed in the update list of // the spritecanvas for this frame), must hide it // here, to ensure it's not visible on screen any // longer.
mpSprite->hide();
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