Hi Mike,
One more question about @2x handling on MacOS.
Clearly, in the simple case of someone loading an ordinary "foo.png" and
painting it on a retina display without doing anything special with the
transform, it will be scaled up by 2x to retain proper size.
Also, clearly, if a "f...@2x.png" file exists, it will be loaded
automatically and found to be twice as large and displayed with no
scaling so that it is the same "size".
But, what if in the first step they manually specified the image file
name as "f...@2x.png" (and assuming there is no "foo@2...@2x.png")? Will
it display with its pixels scaled up to double sized because it was the
direct image that they specified? Or, does the system recognize that it
came from a file named @2x and assume that it is a
double-screen-resolution image and paint it the same way it would have
done if it was implicitly loaded as the higher resolution variant of
"foo.png"?
Let me spell out the scenarios:
Scenario 1:
- app is retina-enabled
- app has WxH foo.png media (and no @2x versions)
- app loads image from "foo.png"
- app displays image with standard default scaling on a retina screen
=> result is image takes up 2W x 2H pixels on the retina screen
Scenario 2:
- app is retina-enabled
- app has WxH foo.png media
- app also has 2W x 2H f...@2x.png media
- app loads image from "foo.png"
- app displays image with standard default scaling on a retina screen
=> result is system also loads f...@2x.png and displays it with 2W x 2H
retina pixels on the retina screen - the same physical size as in the
previous example
Scenario 3:
- app is retina-enabled
- app has WxH foo.png media
- app also has 2W x 2H f...@2x.png media
- app loads image from "f...@2x.png" rather than "foo.png"
- app displays image with standard default scaling on a retina screen
=> result is ???
=> I'm guessing that it gets drawn twice the size as Scenario's 1 and 2
because it is no longer relative to the WxH base image?
Scenario 4:
same as Scenario 3, but foo.png doesn't exist, f...@2x.png is the only
version found in the media for the app
=> result is ???
=> I'm guessing the result is the same as Scenario 3
Also, the convention is for the @2x image to be twice the pixel size of
the regular image, but what if it isn't? Is it always drawn at a 0.5x
relative scale because of the implication of the @2x file name, or will
it be dynamically sized for "basew/@2xw, baseh/@2xh" which just usually
works out to 0.5x if the author followed conventions?
...jim
