You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
130 lines
5.7 KiB
130 lines
5.7 KiB
Overall design
|
|
==============
|
|
|
|
* The document (KWDocument) has a list of framesets (KWFrameSet)
|
|
|
|
* Framesets include: text frameset, picture/clipart frameset, table frameset etc.
|
|
|
|
* A frameset has a list of frames, KWFrame. A KWFrame is basically a rectangle
|
|
(KoRect) with a bunch of attributes.
|
|
The frameset contains the contents, like the text or a picture.
|
|
The frames visualize the contents of the frameset.
|
|
Imagine a 10 pages document, with 1 text-frameset and 10 frames, because our
|
|
example author wants to have one frame per page. This means that there is one
|
|
text, and the frames define where on the pages this text is displayed.
|
|
|
|
* About text framesets: they hold a text document (KWTextDocument, which is
|
|
a QTextDocument from the KoText classes - more on KoText later).
|
|
|
|
* About Tables; one table is a KWTableFrameset. This tableframeset contains
|
|
all the cells as its frames. But because the cells have a different text per
|
|
cell, we contain the cells in their own KWTextFrameset.
|
|
|
|
KWTableFrameSet
|
|
| |
|
|
| TextFrames
|
|
Cells +--------+
|
|
| |
|
|
+ ---> KWTextFrameSet |
|
|
| +-> KWFrame <-+
|
|
| |
|
|
+ ---> KWTextFrameSet |
|
|
| +-> KWFrame <-+
|
|
| |
|
|
+ ---> KWTextFrameSet |
|
|
+-> KWFrame <-+
|
|
|
|
* The z-order of the frames (i.e. which one is on top of which)
|
|
is defined by m_zOrder in KWFrame. This number is relative to the other
|
|
frames *on the same page*.
|
|
|
|
Frame tqlayout and pages
|
|
======================
|
|
Generally, the user is free to position frames where he/she wants to.
|
|
|
|
KWTextFrameSet::slotAfterFormatting() takes care of triggering frame
|
|
resizing (AutoExtend frames), creating a new page (AutoCreateNewFrame), etc.
|
|
|
|
However, in Word Processing mode, some frames are special: main text frameset
|
|
(which might include columns), headers, footers, and footnotes. All of those
|
|
are laid out by the KWFrameLayout class, which is triggered by
|
|
KWDocument::recalcFrames.
|
|
|
|
When creating a new page, KWDocument::insertPage takes care of creating the
|
|
followup frames for all frames with newFrameBehavior=Reconnect.
|
|
|
|
The newFrameBehavior called "Copy" means "exact copy of the contents of
|
|
the frame". This is used for headers/footers (but the user can also use
|
|
it for logos and stuff). In such a case we don't copy anything, we simply
|
|
paint the same contents in many pages.
|
|
|
|
In WP mode, removing pages is automatically done by KWDocument::tryRemovingPages().
|
|
|
|
In DTP mode pages are user-controlled (insert and delete page actions),
|
|
but overflowing text can still create a new page as well.
|
|
|
|
The difficulty with frame tqlayout is that in most cases the frame size and
|
|
number depends on the text inside, and the text tqlayout depends on the frames
|
|
(frame width, frames on top, etc.). This is why text tqlayout (formatMore())
|
|
and frame tqlayout (e.g. KWFrameLayout) often call each other, resulting in
|
|
infinite loops when some code goes wrong.
|
|
|
|
Editing
|
|
=======
|
|
To edit the contents of a text frameset (including table cells), the user clicks on it.
|
|
This creates an edit object for the frameset, which will be destroyed as soon as we go
|
|
edit another frameset. This means, in a given view (canvas), there is only one edit
|
|
object at a given moment (for text objects, it's the one with the cursor).
|
|
There is one type of edit object per type of frameset. For instance: KWTextFrameSetEdit.
|
|
|
|
The kotext library provides a base class for the 'text editing' object, it's KoTextView.
|
|
|
|
Custom items
|
|
============
|
|
A custom item is anything (like an inline frame, a variable etc.) that
|
|
is treated as a special character. QTextCustomItem is the base class for
|
|
it, we have KoTextCustomItem in kotext.
|
|
|
|
Inline frames are one kind of custom item. The frame (and its englobing
|
|
frameset) exist as usual, but a KWAnchor instance is created, inserted
|
|
into the text, and linked to the frame. The anchor always has the same size
|
|
as the frame. When the text is flowed, the anchor is positioned, it tells
|
|
the frame to move to the new position.
|
|
|
|
Painting
|
|
========
|
|
Here's how the painting (drawing the stuff on screen, and on printer) works:
|
|
Each frameset is responsible for drawing itself. The base class, KWFrameSet,
|
|
handles the generic code for iterating through the frames, applying the
|
|
"frame is a copy" stuff, drawing the borders, etc. So each specific frameset
|
|
class only has to implement drawFrame (exception for KWTableFrameset though).
|
|
|
|
Painting of text: KWTextFrameset paints the text for each frame, calling
|
|
KoTextDocument::drawWYSIWYG (with flags for "only the changed paragraphs" etc).
|
|
When printing this method delegates to drawWithoutDoubleBuffer.
|
|
Both methods iterate through the paragraphs, and call drawParagWYSIWYG for each
|
|
one to be redrawn. This method implements the double-buffering, paints the
|
|
background color and the space on the right of the paragraph, and calls
|
|
QTextParag::paint(). Its role is to draw series of characters with the same
|
|
formatting at once (in one go). For each set of chars to be painted,
|
|
KoTextParag::drawParagString is called.
|
|
|
|
In short:
|
|
KWFrame::drawContents -> KWTextFrameSet::drawFrame
|
|
-> KoTextDocument::drawWYSIWYG -> KoTextDocument::drawParagWYSIWYG
|
|
-> KoTextParag::paint -> KoTextParag::drawParagString -> KoTextParag::drawParagStringInternal
|
|
|
|
The cursor is also drawn by KoTextParag::paint, which calls KoTextParag::drawCursor.
|
|
The blinking cursor is implemented in KoTextView, which calls a virtual
|
|
drawCursor() method, implemented in KWTextFrameSetEdit.
|
|
|
|
More low-level things
|
|
=====================
|
|
.. such as coordinate systems, font sizes, justified spaces etc.
|
|
See lib/kotext/DESIGN.
|
|
|
|
|
|
Wow, you managed to read this until the end ? Good. "GOTO 10" now ;)
|
|
|
|
David Faure <faure@kde.org>
|