[PATCH 0/1] MR5757: gdi32/text: Make GetTextExtentExPointW() return sizes consistent with ExtTextOutW().

[Nikolay Sivov (＠nsivov)]

Observable issue before this change is that text extent does not match size
of ExtTextOutW() output. The fix is to shape text in similar way before measuring.
Individual extents returned in this case are arguably useless, they do not
match visual output order, and only give an idea on how much each input character
contributed to overall width. To match input character order all intra-line and
intra-item reordering is disabled.

[PATCH 1/1] gdi32/text: Make GetTextExtentExPointW() return sizes consistent with ExtTextOutW().

[Nikolay Sivov]

From: Nikolay Sivov

Observable issue before this change is that text extent does not match size
of ExtTextOutW() output. The fix is to shape text in similar way before measuring.
Individual extents returned in this case are arguably useless, they do not
match visual output order, and only give an idea on how much each input character
contributed to overall width. To match input character order all intra-line and
intra-item reordering is disabled.
---
 dlls/gdi32/text.c | 126 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 119 insertions(+), 7 deletions(-)

diff --git a/dlls/gdi32/text.c b/dlls/gdi32/text.c
index b61c8ed4542..085c5e3afbe 100644
--- a/dlls/gdi32/text.c
+++ b/dlls/gdi32/text.c
@@ -71,6 +71,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(bidi);
 #define WINE_GCPW_LOOSE_RTL 3
 #define WINE_GCPW_DIR_MASK 3
 #define WINE_GCPW_LOOSE_MASK 2
+#define WINE_GCPW_DISABLE_REORDERING 0x10000000

#define odd(x) ((x) & 1)

@@ -350,7 +351,8 @@ static BOOL BIDI_Reorder( HDC hDC,               /* [in] Display DC */
                           INT uCountOut,         /* [in] Size of output buffer */
                           UINT *lpOrder,         /* [out] Logical -> Visual order map */
                           WORD **lpGlyphs,       /* [out] reordered, mirrored, shaped glyphs to display */
-                          INT *cGlyphs )         /* [out] number of glyphs generated */
+                          INT *cGlyphs,          /* [out] number of glyphs generated */
+                          WORD **cluster_map )   /* [out] cluster map for returned glyphs */
 {
     WORD *chartype = NULL;
     BYTE *levels = NULL;
@@ -588,19 +590,30 @@ static BOOL BIDI_Reorder( HDC hDC,               /* [in] Display DC */
             }

for (j = 0; j < nItems; j++)
+            {
                 runOrder[j] = pItems[j].a.s.uBidiLevel;
+                visOrder[j] = j;
+                if (dwWineGCP_Flags & WINE_GCPW_DISABLE_REORDERING)
+                    pItems[j].a.fLogicalOrder = TRUE;
+            }

-            ScriptLayout(nItems, runOrder, visOrder, NULL);
+            if (!(dwWineGCP_Flags & WINE_GCPW_DISABLE_REORDERING))
+                ScriptLayout(nItems, runOrder, visOrder, NULL);

for (j = 0; j < nItems; j++)
             {
+                const WCHAR *text;
+                WORD *cluster_map;
                 int k;
                 int cChars,cOutGlyphs;
+
                 curItem = &pItems[visOrder[j]];

cChars = pItems[visOrder[j]+1].iCharPos - curItem->iCharPos;

-                res = ScriptShape(hDC, &psc, lpString + done + curItem->iCharPos, cChars, cMaxGlyphs, &curItem->a, run_glyphs, pwLogClust, psva, &cOutGlyphs);
+                text = lpString + done + curItem->iCharPos;
+                cluster_map = pwLogClust + done + curItem->iCharPos;
+                res = ScriptShape(hDC, &psc, text, cChars, cMaxGlyphs, &curItem->a, run_glyphs, cluster_map, psva, &cOutGlyphs);
                 while (res == E_OUTOFMEMORY)
                 {
                     WORD *new_run_glyphs = HeapReAlloc(GetProcessHeap(), 0, run_glyphs, sizeof(*run_glyphs) * cMaxGlyphs * 2);
@@ -621,7 +634,7 @@ static BOOL BIDI_Reorder( HDC hDC,               /* [in] Display DC */
                     run_glyphs = new_run_glyphs;
                     psva = new_psva;
                     cMaxGlyphs *= 2;
-                    res = ScriptShape(hDC, &psc, lpString + done + curItem->iCharPos, cChars, cMaxGlyphs, &curItem->a, run_glyphs, pwLogClust, psva, &cOutGlyphs);
+                    res = ScriptShape(hDC, &psc, text, cChars, cMaxGlyphs, &curItem->a, run_glyphs, cluster_map, psva, &cOutGlyphs);
                 }
                 if (res)
                 {
@@ -653,6 +666,11 @@ static BOOL BIDI_Reorder( HDC hDC,               /* [in] Display DC */
                     *lpGlyphs = new_glyphs;
                     for (k = 0; k < cOutGlyphs; k++)
                         (*lpGlyphs)[glyph_i+k] = run_glyphs[k];
+
+                    /* Fix item cluster map indices to be usable with returned glyph array. */
+                    for (k = 0; k < cChars; ++k)
+                        cluster_map[k] += glyph_i;
+
                     glyph_i += cOutGlyphs;
                 }
             }
@@ -664,6 +682,11 @@ static BOOL BIDI_Reorder( HDC hDC,               /* [in] Display DC */
     }
     if (cGlyphs)
         *cGlyphs = glyph_i;
+    if (cluster_map)
+    {
+        *cluster_map = pwLogClust;
+        pwLogClust = NULL;
+    }

ret = TRUE;
 cleanup:
@@ -952,7 +975,7 @@ BOOL WINAPI ExtTextOutW( HDC hdc, INT x, INT y, UINT flags, const RECT *rect,
             ? WINE_GCPW_FORCE_RTL : WINE_GCPW_FORCE_LTR;

BIDI_Reorder( hdc, str, count, GCP_REORDER, bidi_flags, NULL, 0, NULL,
-                      &glyphs, &glyphs_count );
+                      &glyphs, &glyphs_count, NULL );

flags |= ETO_IGNORELANGUAGE;
         if (glyphs)
@@ -1185,7 +1208,7 @@ DWORD WINAPI GetCharacterPlacementW( HDC hdc, const WCHAR *str, INT count, INT m
     else
     {
         BIDI_Reorder( NULL, str, count, flags, WINE_GCPW_FORCE_LTR, result->lpOutString,
-                      set_cnt, result->lpOrder, NULL, NULL );
+                      set_cnt, result->lpOrder, NULL, NULL, NULL );
     }

if (flags & GCP_USEKERNING)
@@ -1317,13 +1340,102 @@ INT WINAPI GetTextFaceW( HDC hdc, INT count, WCHAR *name )
     return NtGdiGetTextFaceW( hdc, count, name, FALSE );
 }

+static unsigned int get_char_cluster_size(unsigned int start, unsigned int count, const WORD *cluster_map,
+        WORD *first_glyph, WORD *last_glyph)
+{
+    unsigned int i, size = 1;
+
+    *first_glyph = cluster_map[start];
+    *last_glyph = *first_glyph;
+
+    for (i = start + 1; i < count; ++i)
+    {
+        if (cluster_map[i] != *first_glyph)
+        {
+            *last_glyph = cluster_map[i] - 1;
+            break;
+        }
+        size++;
+    }
+
+    return size;
+}
+
+static int get_cluster_extent(const INT *dxs, WORD first_glyph, WORD last_glyph)
+{
+    int extent = dxs[last_glyph];
+
+    if (first_glyph)
+        extent -= dxs[first_glyph - 1];
+    return extent;
+}
+
 /***********************************************************************
  *           GetTextExtentExPointW    (GDI32.@)
  */
 BOOL WINAPI GetTextExtentExPointW( HDC hdc, const WCHAR *str, INT count, INT max_ext,
                                    INT *nfit, INT *dxs, SIZE *size )
 {
-    return NtGdiGetTextExtentExW( hdc, str, count, max_ext, nfit, dxs, size, 0 );
+    WORD *glyphs = NULL, *cluster_map = NULL;
+    unsigned int i, j;
+    DC_ATTR *dc_attr;
+    int glyphs_count;
+    UINT bidi_flags;
+    BOOL ret = TRUE;
+
+    if (!(dc_attr = get_dc_attr( hdc ))) return FALSE;
+
+    bidi_flags = dc_attr->text_align & TA_RTLREADING ? WINE_GCPW_FORCE_RTL : WINE_GCPW_FORCE_LTR;
+    bidi_flags |= WINE_GCPW_DISABLE_REORDERING;
+
+    if (nfit) *nfit = 0;
+
+    BIDI_Reorder( hdc, str, count, GCP_REORDER, bidi_flags, NULL, 0, NULL,
+                  &glyphs, &glyphs_count, &cluster_map );
+
+    if (glyphs)
+    {
+        BOOL need_extents = dxs || nfit;
+        INT *glyph_dxs = NULL;
+
+        if (need_extents)
+        {
+            if (!(glyph_dxs = HeapAlloc( GetProcessHeap(), 0, glyphs_count * sizeof(*glyph_dxs) )))
+                ret = FALSE;
+        }
+
+        if (ret)
+            ret = NtGdiGetTextExtentExW( hdc, glyphs, glyphs_count, 0, NULL, glyph_dxs, size, 1 );
+
+        if (ret && need_extents)
+        {
+            unsigned int cluster_size, cluster_extent;
+            WORD first_glyph, last_glyph;
+            int extents = 0;
+
+            for (i = 0; i < count; i += cluster_size)
+            {
+                cluster_size = get_char_cluster_size(i, count, cluster_map, &first_glyph, &last_glyph);
+                cluster_extent = get_cluster_extent(glyph_dxs, first_glyph, last_glyph);
+
+                if (extents + cluster_extent > max_ext) break;
+                if (nfit) *nfit += cluster_size;
+
+                for (j = 0; j < cluster_size; ++j)
+                    dxs[i + j] = extents + cluster_extent / cluster_size;
+
+                extents += cluster_extent;
+            }
+        }
+
+        HeapFree( GetProcessHeap(), 0, glyphs );
+        HeapFree( GetProcessHeap(), 0, glyph_dxs );
+        HeapFree( GetProcessHeap(), 0, cluster_map );
+    }
+    else
+        ret = NtGdiGetTextExtentExW( hdc, str, count, max_ext, nfit, dxs, size, 0 );
+
+    return ret;
 }

/***********************************************************************

[PATCH 0/1] MR5757: gdi32/text: Make GetTextExtentExPointW() return sizes consistent with ExtTextOutW(). - approved

[Huw Davies (＠huw)]

This merge request was approved by Huw Davies.