tdf#160430: Fix glyph bounds calculation, and use basegfx::B2DRectangle

... instead of tools::Rectangle.

Several problems were there:
1. First, a horizontal bounding rectangle was calculated, with due
rounding; and then the result was rotated, and after that, rounded
again. That made the resulting rotated rectangle coordinates very
imprecise.
2. Also, ceil/floor was applied without normalization; and in case
of rotated font, that meant, that sometimes the range could be not
expanded to cover partially covered pixels, but instead collapsed.
3. The rotation to angles other than 90 degree multiples was done
incorrectly, resulting in cut off parts of characters.
4. For 90 degrees, the imprecise result of sin/cos converted 0.0
into values like 3e-16, which then could be ceil'ed up to 1.

Using B2DRectangle and its transform allows to simplify and fix
the calculations easily, and avoids premature rounding. Render of
rotated text of small size is more stable with this change.

Change-Id: Idffd74b9937feb2418ab76a8d325fdaf4ff841b7
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/165553
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
(cherry picked from commit 8962141a12c966b2d891829925e6203bf8d51852)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/165619
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>

3 files changed, 9 insertions, 8 deletions

diff --git a/vcl/inc/font/LogicalFontInstance.hxx b/vcl/inc/font/LogicalFontInstance.hxx
index 40d3c57c4e67..73ba2e26a2b1 100644
--- a/vcl/inc/font/LogicalFontInstance.hxx
+++ b/vcl/inc/font/LogicalFontInstance.hxx
@@ -22,6 +22,7 @@
 #include <sal/config.h>
 
 #include <basegfx/polygon/b2dpolypolygon.hxx>
+#include <basegfx/range/b2drectangle.hxx>
 #include <o3tl/hash_combine.hxx>
 #include <rtl/ref.hxx>
 #include <salhelper/simplereferenceobject.hxx>
@@ -100,7 +101,7 @@ public: // TODO: make data members private
     vcl::font::PhysicalFontFace* GetFontFace() { return m_pFontFace.get(); }
     const ImplFontCache* GetFontCache() const { return mpFontCache; }
 
-    bool GetGlyphBoundRect(sal_GlyphId, tools::Rectangle&, bool) const;
+    bool GetGlyphBoundRect(sal_GlyphId, basegfx::B2DRectangle&, bool) const;
     virtual bool GetGlyphOutline(sal_GlyphId, basegfx::B2DPolyPolygon&, bool) const = 0;
     basegfx::B2DPolyPolygon GetGlyphOutlineUntransformed(sal_GlyphId) const;
 
diff --git a/vcl/inc/impfontcache.hxx b/vcl/inc/impfontcache.hxx
index 5ea19b05d9a5..4d197003b279 100644
--- a/vcl/inc/impfontcache.hxx
+++ b/vcl/inc/impfontcache.hxx
@@ -21,10 +21,10 @@
 
 #include <sal/config.h>
 
+#include <basegfx/range/b2drectangle.hxx>
 #include <rtl/ref.hxx>
 #include <o3tl/lru_map.hxx>
 #include <o3tl/hash_combine.hxx>
-#include <tools/gen.hxx>
 
 #include "font/FontSelectPattern.hxx"
 #include "glyphid.hxx"
@@ -59,7 +59,7 @@ struct GlyphBoundRectCacheHash
     }
 };
 
-typedef o3tl::lru_map<GlyphBoundRectCacheKey, tools::Rectangle,
+typedef o3tl::lru_map<GlyphBoundRectCacheKey, basegfx::B2DRectangle,
                       GlyphBoundRectCacheHash> GlyphBoundRectCache;
 
 class ImplFontCache
@@ -86,8 +86,8 @@ public:
                             LogicalFontInstance* pLogicalFont,
                             int nFallbackLevel, OUString& rMissingCodes );
 
-    bool GetCachedGlyphBoundRect(const LogicalFontInstance *, sal_GlyphId, tools::Rectangle &);
-    void CacheGlyphBoundRect(const LogicalFontInstance *, sal_GlyphId, tools::Rectangle &);
+    bool GetCachedGlyphBoundRect(const LogicalFontInstance*, sal_GlyphId, basegfx::B2DRectangle&);
+    void CacheGlyphBoundRect(const LogicalFontInstance*, sal_GlyphId, basegfx::B2DRectangle&);
 
     void                Invalidate();
 };
diff --git a/vcl/inc/impglyphitem.hxx b/vcl/inc/impglyphitem.hxx
index 1fa8454e2ea8..bb08031f3ab6 100644
--- a/vcl/inc/impglyphitem.hxx
+++ b/vcl/inc/impglyphitem.hxx
@@ -20,8 +20,8 @@
 #ifndef INCLUDED_VCL_IMPGLYPHITEM_HXX
 #define INCLUDED_VCL_IMPGLYPHITEM_HXX
 
+#include <basegfx/range/b2drectangle.hxx>
 #include <o3tl/typed_flags_set.hxx>
-#include <tools/gen.hxx>
 #include <vcl/dllapi.h>
 #include <vcl/rendercontext/SalLayoutFlags.hxx>
 #include <rtl/math.hxx>
@@ -89,7 +89,7 @@ public:
         return bool(m_nFlags & GlyphItemFlags::IS_SAFE_TO_INSERT_KASHIDA);
     }
 
-    inline bool GetGlyphBoundRect(const LogicalFontInstance*, tools::Rectangle&) const;
+    inline bool GetGlyphBoundRect(const LogicalFontInstance*, basegfx::B2DRectangle&) const;
     inline bool GetGlyphOutline(const LogicalFontInstance*, basegfx::B2DPolyPolygon&) const;
     inline void dropGlyph();
 
@@ -121,7 +121,7 @@ public:
 };
 
 bool GlyphItem::GetGlyphBoundRect(const LogicalFontInstance* pFontInstance,
-                                  tools::Rectangle& rRect) const
+                                  basegfx::B2DRectangle& rRect) const
 {
     return pFontInstance->GetGlyphBoundRect(m_aGlyphId, rRect, IsVertical());
 }