[PATCH v5 1/1] gdiplus: fix StringFormatFlagsLineLimit handling

[David Kahurani]

From: David Kahurani

If StringFormatFlagsLineLimit is set, analyze glyph outlines to determine
the required height for drawing. This is to ensure that the whole line is drawn
when we can establish that no clipping will occur and otherwise not draw the
string.

Signed-off-by: David Kahurani 
---
 dlls/gdiplus/gdiplus.c         |  7 ++++
 dlls/gdiplus/gdiplus_private.h |  2 +
 dlls/gdiplus/graphics.c        | 76 +++++++++++++++++++++++++++++++++-
 dlls/gdiplus/graphicspath.c    |  7 ----
 4 files changed, 83 insertions(+), 9 deletions(-)

diff --git a/dlls/gdiplus/gdiplus.c b/dlls/gdiplus/gdiplus.c
index a3c85986ffc..fe15fd477ea 100644
--- a/dlls/gdiplus/gdiplus.c
+++ b/dlls/gdiplus/gdiplus.c
@@ -481,6 +481,13 @@ void delete_element(region_element* element)
     }
 }

+float fromfixedpoint(const FIXED v)
+{
+    float f = ((float)v.fract) / (1<<(sizeof(v.fract)*8));
+    f += v.value;
+    return f;
+}
+
 const char *debugstr_rectf(const RectF* rc)
 {
     if (!rc) return "(null)";
diff --git a/dlls/gdiplus/gdiplus_private.h b/dlls/gdiplus/gdiplus_private.h
index 1bc058b3413..ff1123c6936 100644
--- a/dlls/gdiplus/gdiplus_private.h
+++ b/dlls/gdiplus/gdiplus_private.h
@@ -200,6 +200,8 @@ static inline ARGB color_over_fgpremult(ARGB bg, ARGB fg)
     return (a<<24)|(r<<16)|(g<<8)|b;
 }

+extern float fromfixedpoint(const FIXED);
+
 extern const char *debugstr_rectf(const RectF* rc);

extern const char *debugstr_pointf(const PointF* pt);
diff --git a/dlls/gdiplus/graphics.c b/dlls/gdiplus/graphics.c
index 758889eca06..1992fa6a7a4 100644
--- a/dlls/gdiplus/graphics.c
+++ b/dlls/gdiplus/graphics.c
@@ -5152,6 +5152,71 @@ GpStatus WINGDIPAPI GdipIsVisibleRectI(GpGraphics *graphics, INT x, INT y, INT w
     return GdipIsVisibleRect(graphics, (REAL)x, (REAL)y, (REAL)width, (REAL)height, result);
 }

+static BOOL text_fits(HDC hdc, WCHAR* string, int index, int length, int available_height)
+{
+    GLYPHMETRICS gm;
+    static const MAT2 identity = { {0,1}, {0,0}, {0,0}, {0,1} };
+    TTPOLYGONHEADER *ph = NULL, *origph = NULL;
+    float topmost, bottommost;
+    int i;
+
+    for (i = index; i < index + length; i++)
+    {
+        DWORD len, ofs = 0;
+        char *start;
+
+        len = GetGlyphOutlineW(hdc, string[i], GGO_BEZIER, &gm, 0, NULL, &identity);
+
+        origph = ph = heap_alloc_zero(len);
+
+        len = GetGlyphOutlineW(hdc, string[i], GGO_BEZIER, &gm, len, (char *)ph, &identity);
+        topmost = fromfixedpoint(ph->pfxStart.y);
+        bottommost = fromfixedpoint(ph->pfxStart.y);
+        start = (char *)ph;
+
+        while (ofs < len)
+        {
+            DWORD ofs_start = ofs;
+            ph = (TTPOLYGONHEADER*)&start[ofs];
+
+            if (topmost > fromfixedpoint(ph->pfxStart.y))
+                topmost = fromfixedpoint(ph->pfxStart.y);
+
+            if (bottommost < fromfixedpoint(ph->pfxStart.y))
+                bottommost = fromfixedpoint(ph->pfxStart.y);
+
+            ofs += sizeof(*ph);
+
+            while (ofs - ofs_start < ph->cb)
+            {
+                int j;
+                TTPOLYCURVE *curve = (TTPOLYCURVE*)&start[ofs];
+                ofs += sizeof(TTPOLYCURVE) + (curve->cpfx - 1) * sizeof(POINTFX);
+
+                for (j = 0; j < curve->cpfx; ++j)
+                {
+                     if (topmost > fromfixedpoint(curve->apfx[j].y))
+                         topmost = fromfixedpoint(curve->apfx[j].y);
+
+                     if (bottommost < fromfixedpoint(curve->apfx[j].y))
+                         bottommost = fromfixedpoint(curve->apfx[j].y);
+
+                }
+
+            }
+        }
+
+        heap_free(origph);
+
+        if ((bottommost - topmost) > available_height)
+            break;
+    }
+
+    if (i != index + length) return FALSE;
+
+   return TRUE;
+}
+
 GpStatus gdip_format_string(HDC hdc,
     GDIPCONST WCHAR *string, INT length, GDIPCONST GpFont *font,
     GDIPCONST RectF *rect, GDIPCONST GpStringFormat *format, int ignore_empty_clip,
@@ -5290,9 +5355,16 @@ GpStatus gdip_format_string(HDC hdc,

if(height + size.cy > nheight)
         {
-            if (format->attr & StringFormatFlagsLineLimit)
-                break;
             bounds.Height = nheight - (height + size.cy);
+
+            if (format->attr & StringFormatFlagsLineLimit)
+            {
+                if (!text_fits(hdc, stringdup, sum, lineend, nheight - height))
+                    break;
+
+                bounds.Height = nheight - height;
+            }
+
         }
         else
             bounds.Height = size.cy;
diff --git a/dlls/gdiplus/graphicspath.c b/dlls/gdiplus/graphicspath.c
index fd2622daf0e..7b4aa2119d6 100644
--- a/dlls/gdiplus/graphicspath.c
+++ b/dlls/gdiplus/graphicspath.c
@@ -935,13 +935,6 @@ GpStatus WINGDIPAPI GdipAddPathPolygonI(GpPath *path, GDIPCONST GpPoint *points,
     return status;
 }

-static float fromfixedpoint(const FIXED v)
-{
-    float f = ((float)v.fract) / (1<<(sizeof(v.fract)*8));
-    f += v.value;
-    return f;
-}
-
 struct format_string_args
 {
     GpPath *path;