1/*
2 * Copyright 2011 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "SkTypes.h"
9#undef GetGlyphIndices
10
11#include "SkDWrite.h"
12#include "SkDWriteGeometrySink.h"
13#include "SkEndian.h"
14#include "SkGlyph.h"
15#include "SkHRESULT.h"
16#include "SkMaskGamma.h"
17#include "SkMatrix22.h"
18#include "SkOTTable_EBLC.h"
19#include "SkOTTable_EBSC.h"
20#include "SkOTTable_gasp.h"
21#include "SkOTTable_maxp.h"
22#include "SkPath.h"
23#include "SkScalerContext.h"
24#include "SkScalerContext_win_dw.h"
25#include "SkTScopedComPtr.h"
26#include "SkTypeface_win_dw.h"
27
28#include <dwrite.h>
29#include <dwrite_1.h>
30
31static bool isLCD(const SkScalerContext::Rec& rec) {
32    return SkMask::kLCD16_Format == rec.fMaskFormat ||
33           SkMask::kLCD32_Format == rec.fMaskFormat;
34}
35
36static bool is_hinted_without_gasp(DWriteFontTypeface* typeface) {
37    AutoTDWriteTable<SkOTTableMaximumProfile> maxp(typeface->fDWriteFontFace.get());
38    if (!maxp.fExists) {
39        return false;
40    }
41    if (maxp.fSize < sizeof(SkOTTableMaximumProfile::Version::TT)) {
42        return false;
43    }
44    if (maxp->version.version != SkOTTableMaximumProfile::Version::TT::VERSION) {
45        return false;
46    }
47
48    if (0 == maxp->version.tt.maxSizeOfInstructions) {
49        // No hints.
50        return false;
51    }
52
53    AutoTDWriteTable<SkOTTableGridAndScanProcedure> gasp(typeface->fDWriteFontFace.get());
54    return !gasp.fExists;
55}
56
57/** A PPEMRange is inclusive, [min, max]. */
58struct PPEMRange {
59    int min;
60    int max;
61};
62
63/** If the rendering mode for the specified 'size' is gridfit, then place
64 *  the gridfit range into 'range'. Otherwise, leave 'range' alone.
65 */
66static void expand_range_if_gridfit_only(DWriteFontTypeface* typeface, int size, PPEMRange* range) {
67    AutoTDWriteTable<SkOTTableGridAndScanProcedure> gasp(typeface->fDWriteFontFace.get());
68    if (!gasp.fExists) {
69        return;
70    }
71    if (gasp.fSize < sizeof(SkOTTableGridAndScanProcedure)) {
72        return;
73    }
74    if (gasp->version != SkOTTableGridAndScanProcedure::version0 &&
75        gasp->version != SkOTTableGridAndScanProcedure::version1)
76    {
77        return ;
78    }
79
80    uint16_t numRanges = SkEndianSwap16(gasp->numRanges);
81    if (numRanges > 1024 ||
82        gasp.fSize < sizeof(SkOTTableGridAndScanProcedure) +
83                     sizeof(SkOTTableGridAndScanProcedure::GaspRange) * numRanges)
84    {
85        return;
86    }
87
88    const SkOTTableGridAndScanProcedure::GaspRange* rangeTable =
89            SkTAfter<const SkOTTableGridAndScanProcedure::GaspRange>(gasp.get());
90    int minPPEM = -1;
91    for (uint16_t i = 0; i < numRanges; ++i, ++rangeTable) {
92        int maxPPEM = SkEndianSwap16(rangeTable->maxPPEM);
93        // Test that the size is in range and the range is gridfit only.
94        if (minPPEM < size && size <= maxPPEM &&
95            rangeTable->flags.raw.value == SkOTTableGridAndScanProcedure::GaspRange::behavior::Raw::GridfitMask)
96        {
97            range->min = minPPEM + 1;
98            range->max = maxPPEM;
99            return;
100        }
101        minPPEM = maxPPEM;
102    }
103
104    return;
105}
106
107static bool has_bitmap_strike(DWriteFontTypeface* typeface, PPEMRange range) {
108    {
109        AutoTDWriteTable<SkOTTableEmbeddedBitmapLocation> eblc(typeface->fDWriteFontFace.get());
110        if (!eblc.fExists) {
111            return false;
112        }
113        if (eblc.fSize < sizeof(SkOTTableEmbeddedBitmapLocation)) {
114            return false;
115        }
116        if (eblc->version != SkOTTableEmbeddedBitmapLocation::version_initial) {
117            return false;
118        }
119
120        uint32_t numSizes = SkEndianSwap32(eblc->numSizes);
121        if (numSizes > 1024 ||
122            eblc.fSize < sizeof(SkOTTableEmbeddedBitmapLocation) +
123                         sizeof(SkOTTableEmbeddedBitmapLocation::BitmapSizeTable) * numSizes)
124        {
125            return false;
126        }
127
128        const SkOTTableEmbeddedBitmapLocation::BitmapSizeTable* sizeTable =
129                SkTAfter<const SkOTTableEmbeddedBitmapLocation::BitmapSizeTable>(eblc.get());
130        for (uint32_t i = 0; i < numSizes; ++i, ++sizeTable) {
131            if (sizeTable->ppemX == sizeTable->ppemY &&
132                range.min <= sizeTable->ppemX && sizeTable->ppemX <= range.max)
133            {
134                // TODO: determine if we should dig through IndexSubTableArray/IndexSubTable
135                // to determine the actual number of glyphs with bitmaps.
136
137                // TODO: Ensure that the bitmaps actually cover a significant portion of the strike.
138
139                // TODO: Ensure that the bitmaps are bi-level?
140                if (sizeTable->endGlyphIndex >= sizeTable->startGlyphIndex + 3) {
141                    return true;
142                }
143            }
144        }
145    }
146
147    {
148        AutoTDWriteTable<SkOTTableEmbeddedBitmapScaling> ebsc(typeface->fDWriteFontFace.get());
149        if (!ebsc.fExists) {
150            return false;
151        }
152        if (ebsc.fSize < sizeof(SkOTTableEmbeddedBitmapScaling)) {
153            return false;
154        }
155        if (ebsc->version != SkOTTableEmbeddedBitmapScaling::version_initial) {
156            return false;
157        }
158
159        uint32_t numSizes = SkEndianSwap32(ebsc->numSizes);
160        if (numSizes > 1024 ||
161            ebsc.fSize < sizeof(SkOTTableEmbeddedBitmapScaling) +
162                         sizeof(SkOTTableEmbeddedBitmapScaling::BitmapScaleTable) * numSizes)
163        {
164            return false;
165        }
166
167        const SkOTTableEmbeddedBitmapScaling::BitmapScaleTable* scaleTable =
168                SkTAfter<const SkOTTableEmbeddedBitmapScaling::BitmapScaleTable>(ebsc.get());
169        for (uint32_t i = 0; i < numSizes; ++i, ++scaleTable) {
170            if (scaleTable->ppemX == scaleTable->ppemY &&
171                range.min <= scaleTable->ppemX && scaleTable->ppemX <= range.max) {
172                // EBSC tables are normally only found in bitmap only fonts.
173                return true;
174            }
175        }
176    }
177
178    return false;
179}
180
181static bool both_zero(SkScalar a, SkScalar b) {
182    return 0 == a && 0 == b;
183}
184
185// returns false if there is any non-90-rotation or skew
186static bool is_axis_aligned(const SkScalerContext::Rec& rec) {
187    return 0 == rec.fPreSkewX &&
188           (both_zero(rec.fPost2x2[0][1], rec.fPost2x2[1][0]) ||
189            both_zero(rec.fPost2x2[0][0], rec.fPost2x2[1][1]));
190}
191
192SkScalerContext_DW::SkScalerContext_DW(DWriteFontTypeface* typeface,
193                                       const SkDescriptor* desc)
194        : SkScalerContext(typeface, desc)
195        , fTypeface(SkRef(typeface))
196        , fGlyphCount(-1) {
197
198    // In general, all glyphs should use CLEARTYPE_NATURAL_SYMMETRIC
199    // except when bi-level rendering is requested or there are embedded
200    // bi-level bitmaps (and the embedded bitmap flag is set and no rotation).
201    //
202    // DirectWrite's IDWriteFontFace::GetRecommendedRenderingMode does not do
203    // this. As a result, determine the actual size of the text and then see if
204    // there are any embedded bi-level bitmaps of that size. If there are, then
205    // force bitmaps by requesting bi-level rendering.
206    //
207    // FreeType allows for separate ppemX and ppemY, but DirectWrite assumes
208    // square pixels and only uses ppemY. Therefore the transform must track any
209    // non-uniform x-scale.
210    //
211    // Also, rotated glyphs should have the same absolute advance widths as
212    // horizontal glyphs and the subpixel flag should not affect glyph shapes.
213
214    // A is the total matrix.
215    SkMatrix A;
216    fRec.getSingleMatrix(&A);
217
218    // h is where A maps the horizontal baseline.
219    SkPoint h = SkPoint::Make(SK_Scalar1, 0);
220    A.mapPoints(&h, 1);
221
222    // G is the Givens Matrix for A (rotational matrix where GA[0][1] == 0).
223    SkMatrix G;
224    SkComputeGivensRotation(h, &G);
225
226    // GA is the matrix A with rotation removed.
227    SkMatrix GA(G);
228    GA.preConcat(A);
229
230    // realTextSize is the actual device size we want (as opposed to the size the user requested).
231    // gdiTextSize is the size we request when GDI compatible.
232    // If the scale is negative, this means the matrix will do the flip anyway.
233    SkScalar realTextSize = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
234    // Due to floating point math, the lower bits are suspect. Round carefully.
235    SkScalar gdiTextSize = SkScalarRoundToScalar(realTextSize * 64.0f) / 64.0f;
236    if (gdiTextSize == 0) {
237        gdiTextSize = SK_Scalar1;
238    }
239
240    bool bitmapRequested = SkToBool(fRec.fFlags & SkScalerContext::kEmbeddedBitmapText_Flag);
241    bool treatLikeBitmap = false;
242    bool axisAlignedBitmap = false;
243    if (bitmapRequested) {
244        // When embedded bitmaps are requested, treat the entire range like
245        // a bitmap strike if the range is gridfit only and contains a bitmap.
246        int bitmapPPEM = SkScalarTruncToInt(gdiTextSize);
247        PPEMRange range = { bitmapPPEM, bitmapPPEM };
248        expand_range_if_gridfit_only(typeface, bitmapPPEM, &range);
249        treatLikeBitmap = has_bitmap_strike(typeface, range);
250
251        axisAlignedBitmap = is_axis_aligned(fRec);
252    }
253
254    // If the user requested aliased, do so with aliased compatible metrics.
255    if (SkMask::kBW_Format == fRec.fMaskFormat) {
256        fTextSizeRender = gdiTextSize;
257        fRenderingMode = DWRITE_RENDERING_MODE_ALIASED;
258        fTextureType = DWRITE_TEXTURE_ALIASED_1x1;
259        fTextSizeMeasure = gdiTextSize;
260        fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
261
262    // If we can use a bitmap, use gdi classic rendering and measurement.
263    // This will not always provide a bitmap, but matches expected behavior.
264    } else if (treatLikeBitmap && axisAlignedBitmap) {
265        fTextSizeRender = gdiTextSize;
266        fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_GDI_CLASSIC;
267        fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
268        fTextSizeMeasure = gdiTextSize;
269        fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
270
271    // If rotated but the horizontal text could have used a bitmap,
272    // render high quality rotated glyphs but measure using bitmap metrics.
273    } else if (treatLikeBitmap) {
274        fTextSizeRender = gdiTextSize;
275        fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
276        fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
277        fTextSizeMeasure = gdiTextSize;
278        fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
279
280    // Fonts that have hints but no gasp table get non-symmetric rendering.
281    // Usually such fonts have low quality hints which were never tested
282    // with anything but GDI ClearType classic. Such fonts often rely on
283    // drop out control in the y direction in order to be legible.
284    } else if (is_hinted_without_gasp(typeface)) {
285        fTextSizeRender = gdiTextSize;
286        fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL;
287        fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
288        fTextSizeMeasure = realTextSize;
289        fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
290
291    // The normal case is to use natural symmetric rendering and linear metrics.
292    } else {
293        fTextSizeRender = realTextSize;
294        fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
295        fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
296        fTextSizeMeasure = realTextSize;
297        fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
298    }
299
300    if (this->isSubpixel()) {
301        fTextSizeMeasure = realTextSize;
302        fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
303    }
304
305    // Remove the realTextSize, as that is the text height scale currently in A.
306    SkScalar scale = SkScalarInvert(realTextSize);
307
308    // fSkXform is the total matrix A without the text height scale.
309    fSkXform = A;
310    fSkXform.preScale(scale, scale); //remove the text height scale.
311
312    fXform.m11 = SkScalarToFloat(fSkXform.getScaleX());
313    fXform.m12 = SkScalarToFloat(fSkXform.getSkewY());
314    fXform.m21 = SkScalarToFloat(fSkXform.getSkewX());
315    fXform.m22 = SkScalarToFloat(fSkXform.getScaleY());
316    fXform.dx = 0;
317    fXform.dy = 0;
318
319    // GsA is the non-rotational part of A without the text height scale.
320    SkMatrix GsA(GA);
321    GsA.preScale(scale, scale); //remove text height scale, G is rotational so reorders with scale.
322
323    fGsA.m11 = SkScalarToFloat(GsA.get(SkMatrix::kMScaleX));
324    fGsA.m12 = SkScalarToFloat(GsA.get(SkMatrix::kMSkewY)); // This should be ~0.
325    fGsA.m21 = SkScalarToFloat(GsA.get(SkMatrix::kMSkewX));
326    fGsA.m22 = SkScalarToFloat(GsA.get(SkMatrix::kMScaleY));
327    fGsA.dx = 0;
328    fGsA.dy = 0;
329
330    // fG_inv is G inverse, which is fairly simple since G is 2x2 rotational.
331    fG_inv.setAll(G.get(SkMatrix::kMScaleX), -G.get(SkMatrix::kMSkewX), G.get(SkMatrix::kMTransX),
332                  -G.get(SkMatrix::kMSkewY), G.get(SkMatrix::kMScaleY), G.get(SkMatrix::kMTransY),
333                  G.get(SkMatrix::kMPersp0), G.get(SkMatrix::kMPersp1), G.get(SkMatrix::kMPersp2));
334}
335
336SkScalerContext_DW::~SkScalerContext_DW() {
337}
338
339unsigned SkScalerContext_DW::generateGlyphCount() {
340    if (fGlyphCount < 0) {
341        fGlyphCount = fTypeface->fDWriteFontFace->GetGlyphCount();
342    }
343    return fGlyphCount;
344}
345
346uint16_t SkScalerContext_DW::generateCharToGlyph(SkUnichar uni) {
347    uint16_t index = 0;
348    fTypeface->fDWriteFontFace->GetGlyphIndices(reinterpret_cast<UINT32*>(&uni), 1, &index);
349    return index;
350}
351
352void SkScalerContext_DW::generateAdvance(SkGlyph* glyph) {
353    //Delta is the difference between the right/left side bearing metric
354    //and where the right/left side bearing ends up after hinting.
355    //DirectWrite does not provide this information.
356    glyph->fRsbDelta = 0;
357    glyph->fLsbDelta = 0;
358
359    glyph->fAdvanceX = 0;
360    glyph->fAdvanceY = 0;
361
362    uint16_t glyphId = glyph->getGlyphID();
363    DWRITE_GLYPH_METRICS gm;
364
365    if (DWRITE_MEASURING_MODE_GDI_CLASSIC == fMeasuringMode ||
366        DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode)
367    {
368        HRVM(fTypeface->fDWriteFontFace->GetGdiCompatibleGlyphMetrics(
369                 fTextSizeMeasure,
370                 1.0f, // pixelsPerDip
371                 &fGsA,
372                 DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode,
373                 &glyphId, 1,
374                 &gm),
375             "Could not get gdi compatible glyph metrics.");
376    } else {
377        HRVM(fTypeface->fDWriteFontFace->GetDesignGlyphMetrics(&glyphId, 1, &gm),
378             "Could not get design metrics.");
379    }
380
381    DWRITE_FONT_METRICS dwfm;
382    fTypeface->fDWriteFontFace->GetMetrics(&dwfm);
383    SkScalar advanceX = SkScalarMulDiv(fTextSizeMeasure,
384                                       SkIntToScalar(gm.advanceWidth),
385                                       SkIntToScalar(dwfm.designUnitsPerEm));
386
387    SkVector vecs[1] = { { advanceX, 0 } };
388    if (DWRITE_MEASURING_MODE_GDI_CLASSIC == fMeasuringMode ||
389        DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode)
390    {
391        // DirectWrite produced 'compatible' metrics, but while close,
392        // the end result is not always an integer as it would be with GDI.
393        vecs[0].fX = SkScalarRoundToScalar(advanceX);
394        fG_inv.mapVectors(vecs, SK_ARRAY_COUNT(vecs));
395    } else {
396        fSkXform.mapVectors(vecs, SK_ARRAY_COUNT(vecs));
397    }
398
399    glyph->fAdvanceX = SkScalarToFixed(vecs[0].fX);
400    glyph->fAdvanceY = SkScalarToFixed(vecs[0].fY);
401}
402
403void SkScalerContext_DW::generateMetrics(SkGlyph* glyph) {
404    glyph->fWidth = 0;
405
406    this->generateAdvance(glyph);
407
408    //Measure raster size.
409    fXform.dx = SkFixedToFloat(glyph->getSubXFixed());
410    fXform.dy = SkFixedToFloat(glyph->getSubYFixed());
411
412    FLOAT advance = 0;
413
414    UINT16 glyphId = glyph->getGlyphID();
415
416    DWRITE_GLYPH_OFFSET offset;
417    offset.advanceOffset = 0.0f;
418    offset.ascenderOffset = 0.0f;
419
420    DWRITE_GLYPH_RUN run;
421    run.glyphCount = 1;
422    run.glyphAdvances = &advance;
423    run.fontFace = fTypeface->fDWriteFontFace.get();
424    run.fontEmSize = SkScalarToFloat(fTextSizeRender);
425    run.bidiLevel = 0;
426    run.glyphIndices = &glyphId;
427    run.isSideways = FALSE;
428    run.glyphOffsets = &offset;
429
430    SkTScopedComPtr<IDWriteGlyphRunAnalysis> glyphRunAnalysis;
431    HRVM(fTypeface->fFactory->CreateGlyphRunAnalysis(
432             &run,
433             1.0f, // pixelsPerDip,
434             &fXform,
435             fRenderingMode,
436             fMeasuringMode,
437             0.0f, // baselineOriginX,
438             0.0f, // baselineOriginY,
439             &glyphRunAnalysis),
440         "Could not create glyph run analysis.");
441
442    RECT bbox;
443    HRVM(glyphRunAnalysis->GetAlphaTextureBounds(fTextureType, &bbox),
444         "Could not get texture bounds.");
445
446    glyph->fWidth = SkToU16(bbox.right - bbox.left);
447    glyph->fHeight = SkToU16(bbox.bottom - bbox.top);
448    glyph->fLeft = SkToS16(bbox.left);
449    glyph->fTop = SkToS16(bbox.top);
450}
451
452void SkScalerContext_DW::generateFontMetrics(SkPaint::FontMetrics* mx,
453                                             SkPaint::FontMetrics* my) {
454    if (!(mx || my))
455      return;
456
457    if (mx) {
458        sk_bzero(mx, sizeof(*mx));
459    }
460    if (my) {
461        sk_bzero(my, sizeof(*my));
462    }
463
464    DWRITE_FONT_METRICS dwfm;
465    if (DWRITE_MEASURING_MODE_GDI_CLASSIC == fMeasuringMode ||
466        DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode)
467    {
468        fTypeface->fDWriteFontFace->GetGdiCompatibleMetrics(
469             fTextSizeRender,
470             1.0f, // pixelsPerDip
471             &fXform,
472             &dwfm);
473    } else {
474        fTypeface->fDWriteFontFace->GetMetrics(&dwfm);
475    }
476
477    SkScalar upem = SkIntToScalar(dwfm.designUnitsPerEm);
478    if (mx) {
479        mx->fTop = -fTextSizeRender * SkIntToScalar(dwfm.ascent) / upem;
480        mx->fAscent = mx->fTop;
481        mx->fDescent = fTextSizeRender * SkIntToScalar(dwfm.descent) / upem;
482        mx->fBottom = mx->fDescent;
483        mx->fLeading = fTextSizeRender * SkIntToScalar(dwfm.lineGap) / upem;
484        mx->fXHeight = fTextSizeRender * SkIntToScalar(dwfm.xHeight) / upem;
485        mx->fUnderlineThickness = fTextSizeRender * SkIntToScalar(dwfm.underlineThickness) / upem;
486        mx->fUnderlinePosition = -(fTextSizeRender * SkIntToScalar(dwfm.underlinePosition) / upem);
487
488        mx->fFlags |= SkPaint::FontMetrics::kUnderlineThinknessIsValid_Flag;
489        mx->fFlags |= SkPaint::FontMetrics::kUnderlinePositionIsValid_Flag;
490    }
491
492    if (my) {
493        my->fAscent = -fTextSizeRender * SkIntToScalar(dwfm.ascent) / upem;
494        my->fDescent = fTextSizeRender * SkIntToScalar(dwfm.descent) / upem;
495        my->fLeading = fTextSizeRender * SkIntToScalar(dwfm.lineGap) / upem;
496        my->fXHeight = fTextSizeRender * SkIntToScalar(dwfm.xHeight) / upem;
497        my->fUnderlineThickness = fTextSizeRender * SkIntToScalar(dwfm.underlineThickness) / upem;
498        my->fUnderlinePosition = -(fTextSizeRender * SkIntToScalar(dwfm.underlinePosition) / upem);
499
500        my->fFlags |= SkPaint::FontMetrics::kUnderlineThinknessIsValid_Flag;
501        my->fFlags |= SkPaint::FontMetrics::kUnderlinePositionIsValid_Flag;
502
503        if (NULL != fTypeface->fDWriteFontFace1.get()) {
504            DWRITE_FONT_METRICS1 dwfm1;
505            fTypeface->fDWriteFontFace1->GetMetrics(&dwfm1);
506            my->fTop = -fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxTop) / upem;
507            my->fBottom = -fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxBottom) / upem;
508            my->fXMin = fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxLeft) / upem;
509            my->fXMax = fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxRight) / upem;
510
511            my->fMaxCharWidth = my->fXMax - my->fXMin;
512        } else {
513            AutoTDWriteTable<SkOTTableHead> head(fTypeface->fDWriteFontFace.get());
514            if (head.fExists &&
515                head.fSize >= sizeof(SkOTTableHead) &&
516                head->version == SkOTTableHead::version1)
517            {
518                my->fTop = -fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->yMax) / upem;
519                my->fBottom = -fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->yMin) / upem;
520                my->fXMin = fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->xMin) / upem;
521                my->fXMax = fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->xMax) / upem;
522
523                my->fMaxCharWidth = my->fXMax - my->fXMin;
524            } else {
525                my->fTop = my->fAscent;
526                my->fBottom = my->fDescent;
527            }
528        }
529    }
530}
531
532///////////////////////////////////////////////////////////////////////////////
533
534#include "SkColorPriv.h"
535
536static void bilevel_to_bw(const uint8_t* SK_RESTRICT src, const SkGlyph& glyph) {
537    const int width = glyph.fWidth;
538    const size_t dstRB = (width + 7) >> 3;
539    uint8_t* SK_RESTRICT dst = static_cast<uint8_t*>(glyph.fImage);
540
541    int byteCount = width >> 3;
542    int bitCount = width & 7;
543
544    for (int y = 0; y < glyph.fHeight; ++y) {
545        if (byteCount > 0) {
546            for (int i = 0; i < byteCount; ++i) {
547                unsigned byte = 0;
548                byte |= src[0] & (1 << 7);
549                byte |= src[1] & (1 << 6);
550                byte |= src[2] & (1 << 5);
551                byte |= src[3] & (1 << 4);
552                byte |= src[4] & (1 << 3);
553                byte |= src[5] & (1 << 2);
554                byte |= src[6] & (1 << 1);
555                byte |= src[7] & (1 << 0);
556                dst[i] = byte;
557                src += 8;
558            }
559        }
560        if (bitCount > 0) {
561            unsigned byte = 0;
562            unsigned mask = 0x80;
563            for (int i = 0; i < bitCount; i++) {
564                byte |= (src[i]) & mask;
565                mask >>= 1;
566            }
567            dst[byteCount] = byte;
568        }
569        src += bitCount;
570        dst += dstRB;
571    }
572}
573
574template<bool APPLY_PREBLEND>
575static void rgb_to_a8(const uint8_t* SK_RESTRICT src, const SkGlyph& glyph, const uint8_t* table8) {
576    const size_t dstRB = glyph.rowBytes();
577    const U16CPU width = glyph.fWidth;
578    uint8_t* SK_RESTRICT dst = static_cast<uint8_t*>(glyph.fImage);
579
580    for (U16CPU y = 0; y < glyph.fHeight; y++) {
581        for (U16CPU i = 0; i < width; i++) {
582            U8CPU r = *(src++);
583            U8CPU g = *(src++);
584            U8CPU b = *(src++);
585            dst[i] = sk_apply_lut_if<APPLY_PREBLEND>((r + g + b) / 3, table8);
586        }
587        dst = (uint8_t*)((char*)dst + dstRB);
588    }
589}
590
591template<bool APPLY_PREBLEND>
592static void rgb_to_lcd16(const uint8_t* SK_RESTRICT src, const SkGlyph& glyph,
593                         const uint8_t* tableR, const uint8_t* tableG, const uint8_t* tableB) {
594    const size_t dstRB = glyph.rowBytes();
595    const U16CPU width = glyph.fWidth;
596    uint16_t* SK_RESTRICT dst = static_cast<uint16_t*>(glyph.fImage);
597
598    for (U16CPU y = 0; y < glyph.fHeight; y++) {
599        for (U16CPU i = 0; i < width; i++) {
600            U8CPU r = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableR);
601            U8CPU g = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableG);
602            U8CPU b = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableB);
603            dst[i] = SkPack888ToRGB16(r, g, b);
604        }
605        dst = (uint16_t*)((char*)dst + dstRB);
606    }
607}
608
609template<bool APPLY_PREBLEND>
610static void rgb_to_lcd32(const uint8_t* SK_RESTRICT src, const SkGlyph& glyph,
611                         const uint8_t* tableR, const uint8_t* tableG, const uint8_t* tableB) {
612    const size_t dstRB = glyph.rowBytes();
613    const U16CPU width = glyph.fWidth;
614    SkPMColor* SK_RESTRICT dst = static_cast<SkPMColor*>(glyph.fImage);
615
616    for (U16CPU y = 0; y < glyph.fHeight; y++) {
617        for (U16CPU i = 0; i < width; i++) {
618            U8CPU r = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableR);
619            U8CPU g = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableG);
620            U8CPU b = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableB);
621            dst[i] = SkPackARGB32(0xFF, r, g, b);
622        }
623        dst = (SkPMColor*)((char*)dst + dstRB);
624    }
625}
626
627const void* SkScalerContext_DW::drawDWMask(const SkGlyph& glyph) {
628    int sizeNeeded = glyph.fWidth * glyph.fHeight;
629    if (DWRITE_RENDERING_MODE_ALIASED != fRenderingMode) {
630        sizeNeeded *= 3;
631    }
632    if (sizeNeeded > fBits.count()) {
633        fBits.setCount(sizeNeeded);
634    }
635
636    // erase
637    memset(fBits.begin(), 0, sizeNeeded);
638
639    fXform.dx = SkFixedToFloat(glyph.getSubXFixed());
640    fXform.dy = SkFixedToFloat(glyph.getSubYFixed());
641
642    FLOAT advance = 0.0f;
643
644    UINT16 index = glyph.getGlyphID();
645
646    DWRITE_GLYPH_OFFSET offset;
647    offset.advanceOffset = 0.0f;
648    offset.ascenderOffset = 0.0f;
649
650    DWRITE_GLYPH_RUN run;
651    run.glyphCount = 1;
652    run.glyphAdvances = &advance;
653    run.fontFace = fTypeface->fDWriteFontFace.get();
654    run.fontEmSize = SkScalarToFloat(fTextSizeRender);
655    run.bidiLevel = 0;
656    run.glyphIndices = &index;
657    run.isSideways = FALSE;
658    run.glyphOffsets = &offset;
659
660    SkTScopedComPtr<IDWriteGlyphRunAnalysis> glyphRunAnalysis;
661    HRNM(fTypeface->fFactory->CreateGlyphRunAnalysis(&run,
662                                          1.0f, // pixelsPerDip,
663                                          &fXform,
664                                          fRenderingMode,
665                                          fMeasuringMode,
666                                          0.0f, // baselineOriginX,
667                                          0.0f, // baselineOriginY,
668                                          &glyphRunAnalysis),
669         "Could not create glyph run analysis.");
670
671    //NOTE: this assumes that the glyph has already been measured
672    //with an exact same glyph run analysis.
673    RECT bbox;
674    bbox.left = glyph.fLeft;
675    bbox.top = glyph.fTop;
676    bbox.right = glyph.fLeft + glyph.fWidth;
677    bbox.bottom = glyph.fTop + glyph.fHeight;
678    HRNM(glyphRunAnalysis->CreateAlphaTexture(fTextureType,
679                                              &bbox,
680                                              fBits.begin(),
681                                              sizeNeeded),
682         "Could not draw mask.");
683    return fBits.begin();
684}
685
686void SkScalerContext_DW::generateImage(const SkGlyph& glyph) {
687    //Create the mask.
688    const void* bits = this->drawDWMask(glyph);
689    if (!bits) {
690        sk_bzero(glyph.fImage, glyph.computeImageSize());
691        return;
692    }
693
694    //Copy the mask into the glyph.
695    const uint8_t* src = (const uint8_t*)bits;
696    if (DWRITE_RENDERING_MODE_ALIASED == fRenderingMode) {
697        bilevel_to_bw(src, glyph);
698        const_cast<SkGlyph&>(glyph).fMaskFormat = SkMask::kBW_Format;
699    } else if (!isLCD(fRec)) {
700        if (fPreBlend.isApplicable()) {
701            rgb_to_a8<true>(src, glyph, fPreBlend.fG);
702        } else {
703            rgb_to_a8<false>(src, glyph, fPreBlend.fG);
704        }
705    } else if (SkMask::kLCD16_Format == glyph.fMaskFormat) {
706        if (fPreBlend.isApplicable()) {
707            rgb_to_lcd16<true>(src, glyph, fPreBlend.fR, fPreBlend.fG, fPreBlend.fB);
708        } else {
709            rgb_to_lcd16<false>(src, glyph, fPreBlend.fR, fPreBlend.fG, fPreBlend.fB);
710        }
711    } else {
712        SkASSERT(SkMask::kLCD32_Format == glyph.fMaskFormat);
713        if (fPreBlend.isApplicable()) {
714            rgb_to_lcd32<true>(src, glyph, fPreBlend.fR, fPreBlend.fG, fPreBlend.fB);
715        } else {
716            rgb_to_lcd32<false>(src, glyph, fPreBlend.fR, fPreBlend.fG, fPreBlend.fB);
717        }
718    }
719}
720
721void SkScalerContext_DW::generatePath(const SkGlyph& glyph, SkPath* path) {
722    SkASSERT(&glyph && path);
723
724    path->reset();
725
726    SkTScopedComPtr<IDWriteGeometrySink> geometryToPath;
727    HRVM(SkDWriteGeometrySink::Create(path, &geometryToPath),
728         "Could not create geometry to path converter.");
729    uint16_t glyphId = glyph.getGlyphID();
730    //TODO: convert to<->from DIUs? This would make a difference if hinting.
731    //It may not be needed, it appears that DirectWrite only hints at em size.
732    HRVM(fTypeface->fDWriteFontFace->GetGlyphRunOutline(SkScalarToFloat(fTextSizeRender),
733                                       &glyphId,
734                                       NULL, //advances
735                                       NULL, //offsets
736                                       1, //num glyphs
737                                       FALSE, //sideways
738                                       FALSE, //rtl
739                                       geometryToPath.get()),
740         "Could not create glyph outline.");
741
742    path->transform(fSkXform);
743}
744