Ensure that the drag image during drag drop operations on Windows is of the correct scale.

Ensure that the drag image width during drag drop on Windows is restricted to 300 pixels

Images above 300 pixels in width are clipped on Windows.

BUG=463483

[ananta, 2015-11-25 22:07:59]

ananta@chromium.org changed reviewers:
+ sky@chromium.org

[sky, 2015-11-25 23:32:55]

https://codereview.chromium.org/1475263002/diff/1/ui/base/dragdrop/drag_utils...
File ui/base/dragdrop/drag_utils_win.cc (right):

https://codereview.chromium.org/1475263002/diff/1/ui/base/dragdrop/drag_utils...
ui/base/dragdrop/drag_utils_win.cc:69: if
(image_skia.HasRepresentation(gfx::GetDPIScale())) {
If it doesn't have a rep for the specified dpi, shouldn't you fallback to the
closest one?

[ananta, 2015-11-25 23:37:14]

https://codereview.chromium.org/1475263002/diff/1/ui/base/dragdrop/drag_utils...
File ui/base/dragdrop/drag_utils_win.cc (right):

https://codereview.chromium.org/1475263002/diff/1/ui/base/dragdrop/drag_utils...
ui/base/dragdrop/drag_utils_win.cc:69: if
(image_skia.HasRepresentation(gfx::GetDPIScale())) {
On 2015/11/25 23:32:54, sky wrote:
> If it doesn't have a rep for the specified dpi, shouldn't you fallback to the
> closest one?

My bad. We should just use GetRepresentation which does the magic, i.e. returns
the closest matching representation

[sky, 2015-11-25 23:38:43]

https://codereview.chromium.org/1475263002/diff/20001/ui/base/dragdrop/drag_u...
File ui/base/dragdrop/drag_utils_win.cc (right):

https://codereview.chromium.org/1475263002/diff/20001/ui/base/dragdrop/drag_u...
ui/base/dragdrop/drag_utils_win.cc:62: const gfx::Vector2d& cursor_offset,
I suspect you need to adjust cursor_offset too.

[ananta, 2015-12-01 02:30:56]

Description was changed from

==========
Ensure that the drag image during drag drop operations on Windows is of the
correct scale.

The drag image currently looks distorted on high dpi displays as the code was
always using the 1x bitmap.

BUG=463483
==========

to

==========
Ensure that the drag image width during drag drop on Windows is restricted to
300 pixels

Images above 300 pixels in width are clipped on Windows.

BUG=463483
==========

[ananta, 2015-12-01 02:42:28]

The FindRepresentation codepath which I was originally trying to fix works
correctly. It returns the closest matching scale to 1 which for high dpi systems
would be the higher dpi image. The actual bug is the drag image width on Windows
cannot be more than 300 pixels. Fixed that. 

While this patch works, the actual fix needs to be in blink. I am working on
that. Will send out a patch for that in a day or two.

I also fixed the cursor positioning issue

https://codereview.chromium.org/1475263002/diff/20001/ui/base/dragdrop/drag_u...
File ui/base/dragdrop/drag_utils_win.cc (right):

https://codereview.chromium.org/1475263002/diff/20001/ui/base/dragdrop/drag_u...
ui/base/dragdrop/drag_utils_win.cc:62: const gfx::Vector2d& cursor_offset,
On 2015/11/25 23:38:43, sky wrote:
> I suspect you need to adjust cursor_offset too.

Done.

[ananta, 2015-12-01 02:47:07]

https://codereview.chromium.org/1475263002/diff/100001/ui/base/dragdrop/drag_...
File ui/base/dragdrop/drag_utils_win.cc (right):

https://codereview.chromium.org/1475263002/diff/100001/ui/base/dragdrop/drag_...
ui/base/dragdrop/drag_utils_win.cc:40: std::min<int>(kMaxDragImageWidth,
sdi.sizeDragImage.cx);
If the width is more than 300 the bitmap is displayed clipped but is still
better than what we see today. Once the blink fix lands it should be better.