office-gobmx/svx
Khaled Hosny 3901e029bd tdf#104921: Cleanup Kashida insertion logic
Communicate Kashida insertion positions in an explicit way.

Rest of LibreOffice communicate adjustments to character widths (e.g.
for justification or spacing) using so-called DX array. DX array is an
array of absolute character positions (e.g. DX[n] is the position after
character n from the start of the lines, and its widths is DX[n] -
DX[n-1]).

This DX array is modified also when Kashidas are inserted after a given
character for Arabic justification, by expanding its width. VCL would
use this to know where to insert the Kashidas and how many ones.

But because DX array is used for both widths adjustments and kashida
insertion, this turns out to be a source of bugs since VCL has tosecond
guess the DX array to find which is pure width adjustment and which also
involves Kashida insertion, and the heuristics it uses are fragile.

This change adds a second array of booleans that records where Kashida
is inserted and communicates it all the way from where Kashida insertion
is decoded in Writer and down to VCL layout.

This change passes the Kashida array only when it seems necessary (e.g.
during drawing but not when measuring text since the DX array is enough
in this case). Hopefully no places where Kashida insertion needs to be
passed down were missed.

A couple of glyph and layout flags that were used for old heuristics and
no longer needed and are removed.

This also fixes:
tdf#87731
tdf#106309
tdf#108604
tdf#112849
tdf#114257
tdf#127176
tdf#145647
tdf#146199

Change-Id: I4ed0850ef2fdc3e9143341afac649e7e7d463c39
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/138068
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
2022-08-14 21:10:24 +02:00
..
doc
inc Fix typo 2022-08-12 10:44:25 +02:00
qa some --disable-pdfium fixes 2022-08-11 17:13:05 +02:00
sdi
source tdf#104921: Cleanup Kashida insertion logic 2022-08-14 21:10:24 +02:00
uiconfig/ui gtk4: set draw-as-radio explicitly on 2022-08-08 22:24:37 +02:00
util
AllLangMoTarget_svx.mk
CppunitTest_svx_core.mk
CppunitTest_svx_dialogs_test.mk
CppunitTest_svx_gallery_test.mk
CppunitTest_svx_removewhichrange.mk
CppunitTest_svx_styles.mk
CppunitTest_svx_unit.mk
Executable_gengal.mk
IwyuFilter_svx.yaml
JunitTest_svx_unoapi.mk
Library_svx.mk
Library_svxcore.mk
Library_textconversiondlgs.mk
Makefile
Module_svx.mk
Package_gengal.mk
README.md
UIConfig_svx.mk
UITest_svx_table.mk

Graphics Related Helper Code

Contains graphics related helper code. Lots of the draw and impress code is in this shared library.

  • xoutdev

    this is where a lot of wht work would happen to move to the canvas. (what does that mean?)

  • svdraw

    transparent gradient stuff. [seriously? surely much more, too]

SdrObject

The shapes you can see in LibreOffice (like rectangle, etc.) are SdrObjects. They are declared as a hierarchy:

SdrObject <- SdrAttrObj <- E3dObject <- E3dCompoundObject <- E3dCubeObj
    ^ ^ ^             ^            ^              | | ^ ^
    | | |             |            |              | | | +--- E3dExtrudeObj
    | | |             |            |              | | +----- E3dLatheObj
    | | |             |            |              | +------- E3dPolygonObj
    | | |             |            |              +--------- E3dSphereObj
    | | |             |            +--- E3dScene...
    | | |             |
    | | |             +--- SdrTextObj <- SdrObjCustomShape...
    | | |                   ^ ^ ^ ^ ^
    | | |                   | | | | +--- SdrEdgeObj...
    | | |                   | | | +----- SdrMeasureObj...
    | | |                   | | +------- SdrPathObj...
    | | |                   | +--------- SdrRectObj...
    | | |                   +----------- SdrTableObj...
    | | +--- SdrObjGroup...
    | + ---- SdrPageObj...
    +------- SdrVirtObj...

The above is incomplete of course.

SdrModel / SdrView

Copied from svdview.hxx:

First of all the app creates a SdrModel. Then it opens a Win and creates a SdrView. ShowSdrPage() announces a page at SdrView. It's possible to show SdrView in any Wins at once.

SdrView can show as many Wins as it wants at once. Pages are announced or checked out with the help of ShowSdrPage()/HideSdrPage(). For every announced page there is a SdrPageView instance in container aPages. If more than one page is showed, you have to pay attention that the offset parameter of ShowSdrPage() is conformed to the size of the page (to prevent overlapping of two pages).

SdrView itself is inherited from many objects in a chain of inheritance (all that starts with SdrPaintView - that is itself inherited from few classes too):

SdrPaintView <- SdrSnapView <- SdrMarkView <- SdrEditView <- SdrPolyEditView
                                                                 ^
+----------------------------------------------------------------+
|
SdrGlueEditView <- SdrObjEditView <- SdrExchangeView <- SdrDragView
                                                                 ^
+----------------------------------------------------------------+
|
SdrCreateView <- SdrView

From SdrView on, it is not flat, but a real hierarchy again.

Drawing Layer / SdrObject(s)

See drawinglayer/README.md for general information about drawinglayer.

Below is the class diagram that comes from https://web.archive.org/web/20160827020830if_/http://www.openoffice.org:80/marketing/ooocon2006/presentations/wednesday_g11.odp slide number 6.

.------- Model --------------.      .------- View -----------------------------------------.
| SdrObject - ViewContact    | 1..* | ViewObjectContact                                    |
|              getChild()    |------|    getPrimitiveList()  -----> Object(s) ---> SdrView |
|              getVOC()      |      |    getRecPrimitiveList()      Contact                |
|              getViewInd... |      |________|_____________________________________________|
| ...ependentPrimitiveList() |               |
|____________________________|            generates
                                             |           ______
                                             V          /      |
                                   .----------------------.    |
                                   | basePrimitive        |    |
                                   |   getRange()         |<---'
                                   |   getDecomposition() |
                                   |______________________|

For SdrObjects, there are own DrawingLayer primitives in svx/source/sdr/primitive2d

The ViewContact / ViewObject / ViewObjectContact are in svx/source/sdr/contact Decomposes the SdrObjects, and does all sort of operations on them.

If the number of visualizable objects (e.g. SdrObjects) is X, and the number of SdrViews is Y, then:

  • there are X ViewContact instances (1:1 relation with a visualizable object)
  • there are Y ObjectContact instances (1:1 relation with an SdrView)
  • there are X*Y ViewObjectContact instances (1:N relation to both visualizable objects and SdrViews)