tdf#152533: Improve script handling in font preview

Use Edit Engine to get the script types instead of trying to duplicate
(poorly) its behaviour. This has the advantage of handling weak
characters and digits properly and is closer to what would happen in the
document itself.

We probably should go further and render the preview entirely using Edit
Engine (since the current code fails short of proper bidi handling), but
this is a bigger change.

Change-Id: I975cb2d96a4a18dbd8110686ca09649cab0ec2f1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/144284
Tested-by: Jenkins
Reviewed-by: خالد حسني <khaled@aliftype.com>

1 files changed, 49 insertions, 70 deletions

diff --git a/svx/source/dialog/fntctrl.cxx b/svx/source/dialog/fntctrl.cxx
index 393fc4e68103..0712bbe92496 100644
--- a/svx/source/dialog/fntctrl.cxx
+++ b/svx/source/dialog/fntctrl.cxx
@@ -23,10 +23,6 @@
 #include <vcl/metric.hxx>
 #include <vcl/svapp.hxx>
 #include <vcl/settings.hxx>
-#include <unicode/uchar.h>
-#include <com/sun/star/uno/Reference.h>
-#include <com/sun/star/i18n/BreakIterator.hpp>
-#include <comphelper/processfactory.hxx>
 
 #include <com/sun/star/i18n/ScriptType.hpp>
 
@@ -46,6 +42,7 @@
 #include <svl/cjkoptions.hxx>
 #include <svl/ctloptions.hxx>
 
+#include <editeng/editeng.hxx>
 #include <editeng/colritem.hxx>
 #include <editeng/fontitem.hxx>
 #include <editeng/editids.hrc>
@@ -72,8 +69,6 @@
 
 using namespace ::com::sun::star::uno;
 using namespace ::com::sun::star::lang;
-using ::com::sun::star::i18n::XBreakIterator;
-using ::com::sun::star::i18n::BreakIterator;
 
 
 // small helper functions to set fonts
@@ -127,6 +122,19 @@ OUString removeCRLF(const OUString& rText)
     return rText.replace(0xa, ' ').replace(0xd, ' ').trim();
 }
 
+struct ScriptInfo
+{
+    tools::Long textWidth;
+    SvtScriptType scriptType;
+    sal_Int32 changePos;
+    ScriptInfo(SvtScriptType scrptType, sal_Int32 position)
+        : textWidth(0)
+        , scriptType(scrptType)
+        , changePos(position)
+    {
+    }
+};
+
 } // end anonymous namespace
 
 class FontPrevWin_Impl
@@ -137,10 +145,7 @@ class FontPrevWin_Impl
     VclPtr<Printer> mpPrinter;
     bool mbDelPrinter;
 
-    Reference <XBreakIterator> mxBreak;
-    std::vector<tools::Long> maTextWidth;
-    std::deque<sal_Int32> maScriptChg;
-    std::vector<sal_uInt16> maScriptType;
+    std::vector<ScriptInfo> maScriptChanges;
     SvxFont maCJKFont;
     SvxFont maCTLFont;
     OUString maText;
@@ -236,45 +241,18 @@ void FontPrevWin_Impl::CheckScript()
     }
 
     maScriptText = maText;
+    maScriptChanges.clear();
 
-    maScriptChg.clear();
-    maScriptType.clear();
-    maTextWidth.clear();
+    auto aEditEngine = EditEngine(nullptr);
+    aEditEngine.SetText(maScriptText);
 
-    if (!mxBreak.is())
+    auto aScript = aEditEngine.GetScriptType({ 0, 0, 0, 0 });
+    for (sal_Int32 i = 1; i <= maScriptText.getLength(); i++)
     {
-        Reference<XComponentContext> xContext = ::comphelper::getProcessComponentContext();
-        mxBreak = BreakIterator::create(xContext);
-    }
-
-    sal_uInt16 nScript = 0;
-    sal_Int32 nChg = 0;
-
-    while (nChg < maText.getLength())
-    {
-        nScript = mxBreak->getScriptType(maText, nChg);
-        nChg = mxBreak->endOfScript(maText, nChg, nScript);
-        if (nChg < maText.getLength() && nChg > 0 &&
-            (css::i18n::ScriptType::WEAK ==
-             mxBreak->getScriptType(maText, nChg - 1)))
-        {
-            int8_t nType = u_charType(maText[nChg]);
-            if (nType == U_NON_SPACING_MARK || nType == U_ENCLOSING_MARK ||
-                nType == U_COMBINING_SPACING_MARK)
-            {
-                maScriptChg.push_back(nChg - 1);
-            }
-            else
-            {
-                maScriptChg.push_back(nChg);
-            }
-        }
-        else
-        {
-            maScriptChg.push_back(nChg);
-        }
-        maScriptType.push_back(nScript);
-        maTextWidth.push_back(0);
+        auto aNextScript = aEditEngine.GetScriptType({ 0, i, 0, i });
+        if (aNextScript != aScript || i == maScriptText.getLength())
+            maScriptChanges.emplace_back(aScript, i);
+        aScript = aNextScript;
     }
 }
 
@@ -290,21 +268,21 @@ void FontPrevWin_Impl::CheckScript()
 
 Size FontPrevWin_Impl::CalcTextSize(vcl::RenderContext& rRenderContext, OutputDevice const * _pPrinter, const SvxFont& rInFont)
 {
-    sal_uInt16 nScript;
+    SvtScriptType aScript;
     sal_uInt16 nIdx = 0;
     sal_Int32 nStart = 0;
     sal_Int32 nEnd;
-    size_t nCnt = maScriptChg.size();
+    size_t nCnt = maScriptChanges.size();
 
     if (nCnt)
     {
-        nEnd = maScriptChg[nIdx];
-        nScript = maScriptType[nIdx];
+        nEnd = maScriptChanges[nIdx].changePos;
+        aScript = maScriptChanges[nIdx].scriptType;
     }
     else
     {
         nEnd = maText.getLength();
-        nScript = css::i18n::ScriptType::LATIN;
+        aScript = SvtScriptType::LATIN;
     }
     tools::Long nTxtWidth = 0;
     tools::Long nCJKHeight = 0;
@@ -316,24 +294,24 @@ Size FontPrevWin_Impl::CalcTextSize(vcl::RenderContext& rRenderContext, OutputDe
 
     do
     {
-        const SvxFont& rFont = (nScript == css::i18n::ScriptType::ASIAN) ?
+        const SvxFont& rFont = (aScript == SvtScriptType::ASIAN) ?
                                     maCJKFont :
-                                    ((nScript == css::i18n::ScriptType::COMPLEX) ?
+                                    ((aScript == SvtScriptType::COMPLEX) ?
                                         maCTLFont :
                                         rInFont);
         tools::Long nWidth = rFont.GetTextSize(*_pPrinter, maText, nStart, nEnd - nStart).Width();
-        if (nIdx >= maTextWidth.size())
+        if (nIdx >= maScriptChanges.size())
             break;
 
-        maTextWidth[nIdx++] = nWidth;
+        maScriptChanges[nIdx++].textWidth = nWidth;
         nTxtWidth += nWidth;
 
-        switch (nScript)
+        switch (aScript)
         {
-            case css::i18n::ScriptType::ASIAN:
+            case SvtScriptType::ASIAN:
                 calcFontHeightAnyAscent(rRenderContext, maCJKFont, nCJKHeight, nCJKAscent);
                 break;
-            case css::i18n::ScriptType::COMPLEX:
+            case SvtScriptType::COMPLEX:
                 calcFontHeightAnyAscent(rRenderContext, maCTLFont, nCTLHeight, nCTLAscent);
                 break;
             default:
@@ -343,8 +321,8 @@ Size FontPrevWin_Impl::CalcTextSize(vcl::RenderContext& rRenderContext, OutputDe
         if (nEnd < maText.getLength() && nIdx < nCnt)
         {
             nStart = nEnd;
-            nEnd = maScriptChg[nIdx];
-            nScript = maScriptType[nIdx];
+            nEnd = maScriptChanges[nIdx].changePos;
+            aScript = maScriptChanges[nIdx].scriptType;
         }
         else
             break;
@@ -383,38 +361,39 @@ Size FontPrevWin_Impl::CalcTextSize(vcl::RenderContext& rRenderContext, OutputDe
 void FontPrevWin_Impl::DrawPrev(vcl::RenderContext& rRenderContext, Printer* _pPrinter, Point &rPt, const SvxFont& rInFont)
 {
     vcl::Font aOldFont = _pPrinter->GetFont();
-    sal_uInt16 nScript;
+    SvtScriptType aScript;
     sal_uInt16 nIdx = 0;
     sal_Int32 nStart = 0;
     sal_Int32 nEnd;
-    size_t nCnt = maScriptChg.size();
+    size_t nCnt = maScriptChanges.size();
+
     if (nCnt)
     {
-        nEnd = maScriptChg[nIdx];
-        nScript = maScriptType[nIdx];
+        nEnd = maScriptChanges[nIdx].changePos;
+        aScript = maScriptChanges[nIdx].scriptType;
     }
     else
     {
         nEnd = maText.getLength();
-        nScript = css::i18n::ScriptType::LATIN;
+        aScript = SvtScriptType::LATIN;
     }
     do
     {
-        const SvxFont& rFont = (nScript == css::i18n::ScriptType::ASIAN)
+        const SvxFont& rFont = (aScript == SvtScriptType::ASIAN)
                                     ? maCJKFont
-                                    : ((nScript == css::i18n::ScriptType::COMPLEX)
+                                    : ((aScript == SvtScriptType::COMPLEX)
                                         ? maCTLFont
                                         : rInFont);
         _pPrinter->SetFont(rFont);
 
         rFont.DrawPrev(&rRenderContext, _pPrinter, rPt, maText, nStart, nEnd - nStart);
 
-        rPt.AdjustX(maTextWidth[nIdx++] );
+        rPt.AdjustX(maScriptChanges[nIdx++].textWidth);
         if (nEnd < maText.getLength() && nIdx < nCnt)
         {
             nStart = nEnd;
-            nEnd = maScriptChg[nIdx];
-            nScript = maScriptType[nIdx];
+            nEnd = maScriptChanges[nIdx].changePos;
+            aScript = maScriptChanges[nIdx].scriptType;
         }
         else
             break;