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Fix text baseline position for some fonts #669

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Fix text baseline position for some fonts #669

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ec118b8
Fix text baseline position for some fonts
PreferLinux Sep 1, 2020
428fda6
Fixes
PreferLinux Sep 3, 2020
6b5f226
Add test
PreferLinux Sep 3, 2020
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5 changes: 3 additions & 2 deletions src/graphics-path.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1273,6 +1273,7 @@ GdipAddPathString (GpPath *path, GDIPCONST WCHAR *string, int length,
{
GpRectF box;
GpPointF box_offset;
float baseline_offset;
PangoLayout* layout;
GpStringFormat *string_format;

Expand All @@ -1296,8 +1297,8 @@ GdipAddPathString (GpPath *path, GDIPCONST WCHAR *string, int length,
return status;
}

layout = gdip_pango_setup_layout (cr, string, length, font, layoutRect, &box, &box_offset, string_format, NULL);
cairo_move_to (cr, layoutRect->X + box_offset.X, layoutRect->Y + box_offset.Y);
layout = gdip_pango_setup_layout (cr, string, length, font, layoutRect, &box, &box_offset, &baseline_offset, string_format, NULL);
cairo_move_to (cr, layoutRect->X + box_offset.X, layoutRect->Y + box_offset.Y + baseline_offset);
pango_cairo_layout_path (cr, layout);
g_object_unref (layout);

Expand Down
2 changes: 1 addition & 1 deletion src/text-pango-private.h
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Expand Up @@ -47,7 +47,7 @@


PangoLayout* gdip_pango_setup_layout (cairo_t *cr, GDIPCONST WCHAR *stringUnicode, INT length, GDIPCONST GpFont *font,
GDIPCONST RectF *rc, RectF *box, PointF *box_offset, GDIPCONST GpStringFormat *format, INT **charsRemoved);
GDIPCONST RectF *rc, RectF *box, PointF *box_offset, float *baseline_offset, GDIPCONST GpStringFormat *format, INT **charsRemoved);

GpStatus pango_DrawString (GpGraphics *graphics, GDIPCONST WCHAR *stringUnicode, INT length, GDIPCONST GpFont *font,
GDIPCONST RectF *rc, GDIPCONST GpStringFormat *format, GpBrush *brush) GDIP_INTERNAL;
Expand Down
31 changes: 26 additions & 5 deletions src/text-pango.c
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Expand Up @@ -177,7 +177,7 @@ gdip_process_string (gchar *text, int length, int removeAccelerators, int trimSp

PangoLayout*
gdip_pango_setup_layout (cairo_t *cr, GDIPCONST WCHAR *stringUnicode, int length, GDIPCONST GpFont *font,
GDIPCONST RectF *rc, RectF *box, PointF *box_offset, GDIPCONST GpStringFormat *format, int **charsRemoved)
GDIPCONST RectF *rc, RectF *box, PointF *box_offset, float *baseline_offset, GDIPCONST GpStringFormat *format, int **charsRemoved)
{
GpStringFormat *fmt;
PangoLayout *layout;
Expand Down Expand Up @@ -468,9 +468,25 @@ gdip_pango_setup_layout (cairo_t *cr, GDIPCONST WCHAR *stringUnicode, int length

box_offset->X = 0;
box_offset->Y = 0;
*baseline_offset = 0;

switch (fmt->lineAlignment) {
case StringAlignmentNear:
if (!(fmt->formatFlags & StringFormatFlagsDirectionVertical)) {
// Some fonts have interesting metrics, and cause Pango to position them differently to Windows.
// For instance, Calibri and the free metric-equivalent Carlito. It is positioned higher, because Pango
// uses a different ascent value than Windows. We can handle that by drawing it slightly lower.
USHORT ascent;
USHORT em_size;
if (GdipGetCellAscent(font->family, (INT) font->style, &ascent) == Ok &&
GdipGetEmHeight(font->family, (INT) font->style, &em_size) == Ok) {

int baseline = pango_layout_get_baseline(layout) / PANGO_SCALE;
int correct_baseline = (int) ceil(font->sizeInPixels / em_size * ascent);
if (baseline < correct_baseline)
*baseline_offset = correct_baseline - baseline;
}
}
break;
case StringAlignmentCenter:
box_offset->Y += (FrameHeight - box->Height) * 0.5;
Expand Down Expand Up @@ -528,6 +544,7 @@ pango_DrawString (GpGraphics *graphics, GDIPCONST WCHAR *stringUnicode, INT leng
PangoLayout *layout;
RectF box;
PointF box_offset;
float baseline_offset;

/* Setup cairo */
if (brush) {
Expand All @@ -538,7 +555,7 @@ pango_DrawString (GpGraphics *graphics, GDIPCONST WCHAR *stringUnicode, INT leng

cairo_save (graphics->ct);

layout = gdip_pango_setup_layout (graphics->ct, stringUnicode, length, font, rc, &box, &box_offset, format, NULL);
layout = gdip_pango_setup_layout (graphics->ct, stringUnicode, length, font, rc, &box, &box_offset, &baseline_offset, format, NULL);
if (!layout) {
cairo_restore (graphics->ct);
return OutOfMemory;
Expand All @@ -552,7 +569,7 @@ pango_DrawString (GpGraphics *graphics, GDIPCONST WCHAR *stringUnicode, INT leng
cairo_clip (graphics->ct);
}

gdip_cairo_move_to (graphics, rc->X + box_offset.X, rc->Y + box_offset.Y, FALSE, TRUE);
gdip_cairo_move_to (graphics, rc->X + box_offset.X, rc->Y + box_offset.Y + baseline_offset, FALSE, TRUE);
pango_cairo_show_layout (graphics->ct, layout);

g_object_unref (layout);
Expand All @@ -569,15 +586,17 @@ pango_MeasureString (GpGraphics *graphics, GDIPCONST WCHAR *stringUnicode, INT l
PangoRectangle logical;
PangoLayoutIter *iter;
PointF box_offset;
float baseline_offset;
int *charsRemoved = NULL;

cairo_save (graphics->ct);

layout = gdip_pango_setup_layout (graphics->ct, stringUnicode, length, font, rc, boundingBox, &box_offset, format, &charsRemoved);
layout = gdip_pango_setup_layout (graphics->ct, stringUnicode, length, font, rc, boundingBox, &box_offset, &baseline_offset, format, &charsRemoved);
if (!layout) {
cairo_restore (graphics->ct);
return OutOfMemory;
}
boundingBox->Height += baseline_offset;

if (codepointsFitted || linesFilled) {
int charsFitted;
Expand Down Expand Up @@ -678,6 +697,7 @@ pango_MeasureCharacterRanges (GpGraphics *graphics, GDIPCONST WCHAR *stringUnico
int i, j;
GpRectF boundingBox;
GpPointF box_offset;
float baseline_offset;

if (layoutRect->Width <= 0.0 && layoutRect->Height < 0.0) {
/* special case only if BOTH values are negative */
Expand All @@ -688,7 +708,7 @@ pango_MeasureCharacterRanges (GpGraphics *graphics, GDIPCONST WCHAR *stringUnico

cairo_save (graphics->ct);

layout = gdip_pango_setup_layout (graphics->ct, stringUnicode, length, font, layoutRect, &boundingBox, &box_offset, format, NULL);
layout = gdip_pango_setup_layout (graphics->ct, stringUnicode, length, font, layoutRect, &boundingBox, &box_offset, &baseline_offset, format, NULL);
if (!layout) {
cairo_restore (graphics->ct);
return OutOfMemory;
Expand Down Expand Up @@ -750,6 +770,7 @@ pango_MeasureCharacterRanges (GpGraphics *graphics, GDIPCONST WCHAR *stringUnico
}
charRect.X += box_offset.X + layoutRect->X;
charRect.Y += box_offset.Y + layoutRect->Y;
charRect.Height += baseline_offset;
// g_warning ("[%d] [%d : %d-%d] %c [x %g y %g w %g h %g]", i, j, start, end, (char)stringUnicode[j], charRect.X, charRect.Y, charRect.Width, charRect.Height);
status = GdipCombineRegionRect (regions [i], &charRect, CombineModeUnion);
if (status != Ok)
Expand Down
34 changes: 34 additions & 0 deletions tests/testtext.c
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,12 @@ static void test_measure_string(void)
int glyphs;
int lines;
const SHORT fontSize = 10;
GpFontCollection *collection;
WCHAR *ttfFile;
INT count;
GpFontFamily *families[1];
GpFont *font2;
REAL fontHeight;

status = GdipCreateStringFormat (0, 0, &format);
expect (Ok, status);
Expand Down Expand Up @@ -179,6 +185,34 @@ static void test_measure_string(void)
expect (1, lines);
expectf ((double)fontSize, bounds.Width); // An em-space should be the same width as the font size.

// Check measuring a string drawn with a font that has metrics which cause Pango to draw differently to GDI+
GdipNewPrivateFontCollection (&collection);
ttfFile = createWchar ("test.ttf");
status = GdipPrivateAddFontFile (collection, ttfFile);
expect (Ok, status);
status = GdipGetFontCollectionFamilyList (collection, 2, families, &count);
expect (Ok, status);
expect (1, count);
status = GdipCreateFont (families[0], 36, 0, UnitPixel, &font2);
expect (Ok, status);
status = GdipGetFontHeight (font2, graphics, &fontHeight);
expect (Ok, status);
set_rect_empty (&bounds);
status = GdipMeasureString (graphics, teststring1, 1, font2, &rect, format, &bounds, &glyphs, &lines);
expect (Ok, status);
expectf (5.0, bounds.X);
expectf (5.0, bounds.Y);
expectf_ (20.0, bounds.Width, 3);
expectf_ (fontHeight, bounds.Height, 3);
expect (1, glyphs);
expect (1, lines);
GdipDeleteFont(font2);
// This causes a crash in GDI+.
#if !defined(USE_WINDOWS_GDIPLUS)
GdipDeleteFontFamily (families[0]);
#endif
GdipDeletePrivateFontCollection (&collection);

// MonoTests.System.Drawing.GraphicsTest.MeasureString_Wrapping_Dots
GdipDeleteStringFormat (format);
status = GdipCreateStringFormat (0, 0, &format);
Expand Down