Dev docs

doc/Development Guide.md

@@ -0,0 +1,135 @@
+# Development Guide
+
+The whole frontend part of KOReader is scripted in [Lua](http://www.lua.org/about.html) programming language which means you can start development with just a decent text editor. Instructions about how to get and compile the source of the backend part on a linux OS are [here](https://github.com/koreader/koreader#building-prerequisites)
+
+The source tree of frontend looks like this:
+```
+frontend
+├── apps
+│   ├── filemanager
+│   │   ├── filemanagerhistory.lua
+│   │   ├── filemanager.lua
+│   │   └── filemanagermenu.lua
+│   └── reader *
+│       ├── modules
+│       │   ├── readeractivityindicator.lua
+│       │   ├── readerbookmark.lua
+│       │   ├── readerconfig.lua
+│       │   ├── readercoptlistener.lua
+│       │   ├── readercropping.lua
+│       │   ├── readerdictionary.lua
+│       │   ├── readerdogear.lua
+│       │   ├── readerflipping.lua
+│       │   ├── readerfont.lua
+│       │   ├── readerfooter.lua
+│       │   ├── readerfrontlight.lua
+│       │   ├── readergoto.lua
+│       │   ├── readerhighlight.lua
+│       │   ├── readerhinting.lua
+│       │   ├── readerhyphenation.lua
+│       │   ├── readerkoptlistener.lua
+│       │   ├── readerlink.lua
+│       │   ├── readermenu.lua
+│       │   ├── readerpaging.lua
+│       │   ├── readerpanning.lua
+│       │   ├── readerrolling.lua
+│       │   ├── readerrotation.lua
+│       │   ├── readerscreenshot.lua
+│       │   ├── readertoc.lua
+│       │   ├── readertypeset.lua
+│       │   ├── readerview.lua
+│       │   └── readerzooming.lua
+│       ├── pluginloader.lua
+│       └── readerui.lua
+├── cacheitem.lua
+├── cache.lua
+├── configurable.lua
+├── dbg.lua
+├── docsettings.lua
+├── document *
+│   ├── credocument.lua
+│   ├── djvudocument.lua
+│   ├── document.lua
+│   ├── documentregistry.lua
+│   ├── koptinterface.lua
+│   ├── pdfdocument.lua
+│   ├── picdocument.lua
+│   └── tilecacheitem.lua
+├── gettext.lua
+├── JSON.lua
+├── optmath.lua
+└── ui
+    ├── data
+    │   ├── creoptions.lua
+    │   ├── koptoptions.lua
+    │   └── strings.lua
+    ├── device
+    │   ├── basepowerd.lua
+    │   ├── kindlepowerd.lua
+    │   ├── kobopowerd.lua
+    │   └── screen.lua
+    ├── device.lua
+    ├── event.lua
+    ├── font.lua
+    ├── geometry.lua
+    ├── gesturedetector.lua
+    ├── gesturerange.lua
+    ├── input.lua
+    ├── language.lua
+    ├── rendertext.lua
+    ├── screen.lua
+    ├── timeval.lua
+    ├── uimanager.lua
+    └── widget *
+        ├── bboxwidget.lua
+        ├── buttondialog.lua
+        ├── button.lua
+        ├── buttontable.lua
+        ├── closebutton.lua
+        ├── configdialog.lua
+        ├── confirmbox.lua
+        ├── container
+        │   ├── bottomcontainer.lua
+        │   ├── centercontainer.lua
+        │   ├── framecontainer.lua
+        │   ├── inputcontainer.lua
+        │   ├── leftcontainer.lua
+        │   ├── rightcontainer.lua
+        │   ├── underlinecontainer.lua
+        │   └── widgetcontainer.lua
+        ├── dictquicklookup.lua
+        ├── eventlistener.lua
+        ├── filechooser.lua
+        ├── fixedtextwidget.lua
+        ├── focusmanager.lua
+        ├── horizontalgroup.lua
+        ├── horizontalspan.lua
+        ├── iconbutton.lua
+        ├── imagewidget.lua
+        ├── infomessage.lua
+        ├── inputdialog.lua
+        ├── inputtext.lua
+        ├── linewidget.lua
+        ├── menu.lua
+        ├── notification.lua
+        ├── overlapgroup.lua
+        ├── progresswidget.lua
+        ├── rectspan.lua
+        ├── scrolltextwidget.lua
+        ├── textboxwidget.lua
+        ├── textwidget.lua
+        ├── toggleswitch.lua
+        ├── touchmenu.lua
+        ├── verticalgroup.lua
+        ├── verticalscrollbar.lua
+        ├── verticalspan.lua
+        ├── virtualkeyboard.lua
+        └── widget.lua
+```
+in which you will find the asterisked `frontend/document`, `frontend/apps/reader` and `frontend/ui/widget` the most interesting parts.
+
+### document: API for document parsing and rendering
+
+### reader: reader functionality implementation
+
+### widget: a light-weight widget toolkit

doc/Events.md

@@ -11,6 +11,7 @@ to a widget, you can simply invoke the handleEvent method like the following:
 widget_foo:handleEvent(Event:new("Timeout"))
 ```
 
+Events are passed to child Widgets (or child containers) before their own handler sees them. See the implementation of WidgetContainer:handleEvent(). So a child widget, for instance a text input widget, gets the input events before the layout manager. The child widgets can "consume" an event by returning "true" from the event handler. Thus a text input widget just implements an input handler and consumes left/right presses, returning true in those cases. It can even make its return code dependent on whether the cursor is on the last position (do not consume press to right) or first position (do not consume press to left) to have proper focus movement in those cases.
 
 ## Builtin events ##
 
@@ -43,3 +44,22 @@ end
 return self["on"..event.name](self, unpack(event.args))
 ```
 
+## Event system
+Event system is used for widgets to communicate with each others.
+
+Each event is an object that has two properties: `args` and `handler`. `handler` is the name of function that will be called on receive. `args` is a table that contains all the arguments needed to be passed to the event handler. When a widget receives a event, it will first check to see if `self[event.handler]` exists. If yes, the `self[event.handler]` function will be called and the return value of the handler will be returned to UIManager.
+
+Notice that if you don't want the event propagate after consumed in your handler, your handler must return True. Otherwise, the event will be passed to other widgets' handlers until one of the handlers returns True.
+
+`WidgetContainer` is a special kind of widget. When it receives an event, it will first propagate the event to all its children. If the event is still not consumed (handler returns True), then it will try to handle by itself.
+
+When you call `UIManager:show` on an widget, this widget will be added to the top of `UIManager._window_stack`.
+Events are sent to the first widget in `UIManager._window_stack`. If it is not consumed, then UIManager will try to send it to all active widgets (`widget.is_always_active` equals `true`) in the `_window_stack`.
+
+## Draw Page Code Path
+* **in readerview.lua:** ReaderView widget flag itself dirty in `ReaderView:recalculate`
+* **in ui.lua:** UI main loop calls `ReaderView:paintTo`
+* **in readerview.lua:** `ReaderView:paintTo` calls `document:drawPage`
+* **in document.lua:** `document:drawPage` check for cache, if found, **return cache**
+* **in document.lua:** if cache not found, `document:drawPage` calls `document:renderPage`
+* **in document.lua:** `document:renderPage` calls `_document:openPage`, `page:draw` and put the result into cache

doc/Hacking.md

@@ -1,6 +1,23 @@
 Hacking
 =======
 
+## How to Debug
+
+We have a helper function called `logger.dbg` to help with debugging. You can use that function to print string and tables:
+
+```lua
+local logger = require("logger")
+a = {"1", "2", "3"}
+logger.dbg("table a: ", a)
+```
+
+Anything printed by `logger.dbg` starts with a `#` sign.
+
+## Bug hunting in kpv
+
+A real example for hunting bug in KPV's cache system: https://github.com/koreader/kindlepdfviewer/pull/475
+
+
 ## Developing UI widgets ##
 
 `tools/wbuilder.lua` is your friend, if you need to create new UI widgets. It

doc/Porting.md

@@ -0,0 +1,94 @@
+# Porting
+
+This page aims to provide guidance on how to port KOReader to other platforms.
+
+There are mainly two modules that you need to take care of: input and output.
+After you finish these two, KOReader should have no problem running on your
+platform. Feel free to open issues in our issue tracker if you need further help on this topic :)
+
+
+## Output Module
+
+KOReader uses framebuffer to control EInk devices, so the output module here is
+[einkfb.c][einkfb-c]. You can find this file in koreader-base framework. The
+koreader-base framework used to be part of KOReader, but we later factored it
+out and use it in KOReader as submodule.
+
+Following are the framebuffers that `einkfb.c` currently supports:
+  * 4BPP inverted framebuffer
+  * 16 scale 8BPP inverted framebuffer
+  * 16 scale 8BPP framebuffer
+
+For 4BPP framebuffer, it means every pixel is represented with 4 bits, so we
+have 2 pixels in 1 byte. So the color depth is 16. The inverted part means all
+the bits are flipped in the framebuffer. For example, two pixels `[0x00, 0xf0]`
+will be stored as `0xff0f` in framebuffer.
+
+For 16 scale 8BPP framebuffer, it means each pixel is instead stored in 1 byte,
+but the color depth is still 16 (4bits). Since 1 byte has 8 bits, so to fill
+up the remaining space, the most significant 4 bits is a copy of the least
+significant one. For example, pixel with grey scale 15 will be represented as
+`0xffff`. If it's a inverted 16 scale 8BPP framebuffer, then all the bits are
+flipped in the same way as 4BPP inverted framebuffer does.
+
+If your device's framebuffer does not fit into any of the categories above,
+then you need to add a new transformation function in `einkfb.c`.
+
+The `einkfb.c` module works in following ways for non 4BPP framebuffers;
+  * a shadow buffer is created and structured as 4BPP inverted framebuffer.
+  * all updates on screen bitmap are temporally written into the shadow buffer.
+  * each time we want to reflect the updated bitmap on screen, we translate
+    the shadow buffer into a format that the real framebuffer understands and
+    write into the mapped memory region. (varies on devices)
+  * call ioctl system call to refresh EInk screen. (varies on devices)
+
+KOReader will handle the 4BPP shadow buffer for you, all you need to do is to
+teach `einkfb.c` how to control the EInk screen and translate the 4BPP inverted
+bitmap into the format that your framebuffer understands.
+
+In `openFrameBuffer()` function, the value for a function pointer
+`einkUpdateFunc` is assigned according to devices' model. This function is
+called on every screen refresh. It transforms the shadow buffer and write the
+result into framebuffer. Then it calls ioctl to refresh the screen.
+
+So you need to write a einkUpdateFunction for your device's framebuffer and
+assigned it to `einkUpdateFunc` on eink open. You may want to refer to
+`kindle51einkUpdate()`, `kindle4einkUpdate()` and `kindle3einkUpdate()`
+functions for real examples.
+
+
+
+## Input Module
+
+We have a `input.c` module in [koreader-base][kb-framework] that reads input
+events from Linux's input system and pass to Lua frontend. Basically, you don't
+need to change on that module because it should support most of the events.
+
+For this part, the file you have to hack on is [`koreader/frontend/ui/input.lua`](https://github.com/koreader/koreader/blob/master/frontend/ui/input.lua).
+
+Firstly, you need to tell which input device to open on KOReader start. All the
+input devices are opened in `Input:init()` function.
+
+Next, you might need to define `Input:eventAdjustHook()` function in
+`Input:init()` method. We use this hook function to translates events into a
+format that KOReader understands. You can look at the KindleTouch initialization code for real example.
+
+For Kobo devices (Mini, Touch, Glo and Aura HD) the function `Input:eventAdjustHook()` was skipped and the functions `Input:init()` and `Input:handleTypeBTouchEv` were changed to allow the single touch protocol. For Kobo Aura with multitouch support an extra function `Input:handlePhoenixTouchEv` was added.
+
+Linux supports two kinds of Multi-touch protocols:
+ * http://www.kernel.org/doc/Documentation/input/multi-touch-protocol.txt
+
+Currently, KOReader supports gesture detection of protocol B, so if your device sends out
+protocol A, you need to make a variant of function `Input:handleTouchEv()` (like `Input:handleTypeBTouchEv` and `Input:handlePhoenixTouchEv`) and simulate protocol B.
+Also you are welcome to send a PR that adds protocol A support to KOReader.
+
+More information on Linux's input system:
+ * http://www.kernel.org/doc/Documentation/input/event-codes.txt
+ * http://www.kernel.org/doc/Documentation/input/input.txt
+
+
+
+[einkfb-c]:https://github.com/koreader/koreader-base/blob/master/einkfb.c
+[kb-framework]:https://github.com/koreader/koreader-base
+[inputev]:https://github.com/koreader/koreader/blob/master/frontend/ui/inputevent.lua
+