Make navigating the picture view in debugger more functional.

Make navigating the picture view in debugger more functional.

[bungeman, 2013-01-16 22:53:27]

This changes debugger interaction in the following ways:

1. Scroll wheel scrolls the view.
2. Ctrl+scroll wheel zooms in and out (with the fixed point at the mouse
cursor).
3. Ctrl+dblclick drops the fractional part of the user translation.
4. All zooms (in and out) are by a factor of 1.25.

Internally the separate user translation and zoom factors are replaced by a
single user matrix.

These changes make using the debugger on long pages much easier.

[DerekS, 2013-01-17 13:45:12]

lgtm if the few nits are addressed

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkCanvasWidget.h
File debugger/QT/SkCanvasWidget.h (right):

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkCanvasWidget.h#ne...
debugger/QT/SkCanvasWidget.h:37: void zoom(float zoomPercent, int px, int py);
is px/py the anchor point?  Can you comment what they do?

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkCanvasWidget.h#ne...
debugger/QT/SkCanvasWidget.h:47: void keyZoom(int zoomCommand);
it isn't clear to me what unit of measure zoomCommand is

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkSettingsWidget.h
File debugger/QT/SkSettingsWidget.h (right):

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkSettingsWidget.h#...
debugger/QT/SkSettingsWidget.h:37: void setZoomText(float scaleFactor);
can you put a comment here that that valid range is 0...1?  Perhaps an assert in
the implementation too.

[bungeman, 2013-01-17 16:28:09]

Added comments and clarified parameters.

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkCanvasWidget.h
File debugger/QT/SkCanvasWidget.h (right):

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkCanvasWidget.h#ne...
debugger/QT/SkCanvasWidget.h:37: void zoom(float zoomPercent, int px, int py);
On 2013/01/17 13:45:12, DerekS wrote:
> is px/py the anchor point?  Can you comment what they do?

Yes, zoomPercent is also a really bad name, fixing.
Done.

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkCanvasWidget.h#ne...
debugger/QT/SkCanvasWidget.h:47: void keyZoom(int zoomCommand);
On 2013/01/17 13:45:12, DerekS wrote:
> it isn't clear to me what unit of measure zoomCommand is

It's just zoom in and zoom out. Added enum and changed name.
Done.

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkSettingsWidget.h
File debugger/QT/SkSettingsWidget.h (right):

https://codereview.appspot.com/7134049/diff/1/debugger/QT/SkSettingsWidget.h#...
debugger/QT/SkSettingsWidget.h:37: void setZoomText(float scaleFactor);
On 2013/01/17 13:45:12, DerekS wrote:
> can you put a comment here that that valid range is 0...1?  Perhaps an assert
in
> the implementation too.

The valid range isn't 0...1? It's just for the text box and is just the current
user scale factor. Added a comment.

Done.

[bungeman, 2013-01-17 16:32:30]

Committed revision 7253.

https://codereview.appspot.com/7134049/diff/5001/debugger/QT/SkCanvasWidget.cpp
File debugger/QT/SkCanvasWidget.cpp (right):

https://codereview.appspot.com/7134049/diff/5001/debugger/QT/SkCanvasWidget.c...
debugger/QT/SkCanvasWidget.cpp:119: void SkCanvasWidget::zoom(float zoomPercent,
int px, int py) {
Changed to 'zoomPercent' here to 'scale' before committing.