On 24.11.2016 20:25, Sergey Bylokhov wrote:
On 24.11.16 19:54, Semyon Sadetsky wrote:
"A non-opaque component paints only a subset of its pixels or none at
all...". Per-pixel translucent component paints all its pixels. This is
not clearly states that per-pixel translucent component shall be
non-opaque.
I see an obvious inconsistency in a way we handle translucent JComponent
and Window. This, of cause, need to be resolved somehow. We could
forcibly make JComponent to be non-opaque as well as this is done for
Window, or take translucency into account during the painting.
The Window#isOpaque() spec states:
The method returns false if the background color of the window
is not null and the alpha component of the color is less than 1.0.
Even with this absolutely clear spec the opaque property is set to false
automatically with assigning transparent background to the window, and
it doesn't require from user to keep them consistent.
It have a different implementations because it has different meaning:
- The non-opaque window is a window which uses transparent background.
- The non-opaque component is the component which require the parents
be painted first. it is not necessary that the background in this case
should be transparent(It is possible that the component draw something
only in some place of its bounds) And transparent color is not always
requires that the component should be non-opaque, because components
can ignore its background.
Hmm.. Both JComponent and Window override the same Component.isOpaque()
but the property has different meaning for each of them.
Probably, this is a design mistake?
