this should implement feature request of zoom mode for multi-columns
page in #501
This PR depends on koreader/koreader-base#435
How to use?
1. Tap the top left corner of a PDF/Djvu page to get into the flipping
mode
2. Double-tap on text block will zoom in to that column
3. Double-tap on any area will zoom out to an overview of the page
4. repeat step 2 to focus to another page block
How does it work?
1. We first find the mask of text blocks in the page. (Pic 1)
2. Then we intersect page boxes with user tap to form a page block. (Pic 2)
3. Finally we zoom the page to the page block and center current view to
that block. (Pic 3)
This is the remaining gruntwork of #1276. I believe that only leaves networkmgr.lua and filemanagersearch.lua, which will require a little more thought.
This is a major overhaul of the hardware abstraction layer.
A few notes:
General platform distinction happens in
frontend/device.lua
which will delegate everything else to
frontend/device/<platform_name>/device.lua
which should extend
frontend/device/generic/device.lua
Screen handling is implemented in
frontend/device/screen.lua
which includes the *functionality* to support device specifics.
Actually setting up the device specific functionality, however,
is done in the device specific setup code in the relevant
device.lua file.
The same goes for input handling.
