SkScalerContext_DW::SkScalerContext_DW(DWriteFontTypeface* typeface,
const SkScalerContextEffects& effects,
const SkDescriptor* desc)
: SkScalerContext(typeface, effects, desc)
, fTypeface(SkRef(typeface))
, fGlyphCount(-1) {
#if SK_HAS_DWRITE_2_H
fTypeface->fFactory->QueryInterface<IDWriteFactory2>(&fFactory2);
SkTScopedComPtr<IDWriteFontFace2> fontFace2;
fTypeface->fDWriteFontFace->QueryInterface<IDWriteFontFace2>(&fontFace2);
fIsColorFont = fFactory2.get() && fontFace2.get() && fontFace2->IsColorFont();
#endif
// In general, all glyphs should use CLEARTYPE_NATURAL_SYMMETRIC
// except when bi-level rendering is requested or there are embedded
// bi-level bitmaps (and the embedded bitmap flag is set and no rotation).
//
// DirectWrite's IDWriteFontFace::GetRecommendedRenderingMode does not do
// this. As a result, determine the actual size of the text and then see if
// there are any embedded bi-level bitmaps of that size. If there are, then
// force bitmaps by requesting bi-level rendering.
//
// FreeType allows for separate ppemX and ppemY, but DirectWrite assumes
// square pixels and only uses ppemY. Therefore the transform must track any
// non-uniform x-scale.
//
// Also, rotated glyphs should have the same absolute advance widths as
// horizontal glyphs and the subpixel flag should not affect glyph shapes.
SkVector scale;
SkMatrix GsA;
fRec.computeMatrices(SkScalerContextRec::kVertical_PreMatrixScale,
&scale, &fSkXform, &GsA, &fG_inv);
fXform.m11 = SkScalarToFloat(fSkXform.getScaleX());
fXform.m12 = SkScalarToFloat(fSkXform.getSkewY());
fXform.m21 = SkScalarToFloat(fSkXform.getSkewX());
fXform.m22 = SkScalarToFloat(fSkXform.getScaleY());
fXform.dx = 0;
fXform.dy = 0;
fGsA.m11 = SkScalarToFloat(GsA.get(SkMatrix::kMScaleX));
fGsA.m12 = SkScalarToFloat(GsA.get(SkMatrix::kMSkewY)); // This should be ~0.
fGsA.m21 = SkScalarToFloat(GsA.get(SkMatrix::kMSkewX));
fGsA.m22 = SkScalarToFloat(GsA.get(SkMatrix::kMScaleY));
fGsA.dx = 0;
fGsA.dy = 0;
// realTextSize is the actual device size we want (as opposed to the size the user requested).
// gdiTextSize is the size we request when GDI compatible.
// If the scale is negative, this means the matrix will do the flip anyway.
const SkScalar realTextSize = scale.fY;
// Due to floating point math, the lower bits are suspect. Round carefully.
SkScalar gdiTextSize = SkScalarRoundToScalar(realTextSize * 64.0f) / 64.0f;
if (gdiTextSize == 0) {
gdiTextSize = SK_Scalar1;
}
bool bitmapRequested = SkToBool(fRec.fFlags & SkScalerContext::kEmbeddedBitmapText_Flag);
bool treatLikeBitmap = false;
bool axisAlignedBitmap = false;
if (bitmapRequested) {
// When embedded bitmaps are requested, treat the entire range like
// a bitmap strike if the range is gridfit only and contains a bitmap.
int bitmapPPEM = SkScalarTruncToInt(gdiTextSize);
PPEMRange range = { bitmapPPEM, bitmapPPEM };
expand_range_if_gridfit_only(typeface, bitmapPPEM, &range);
treatLikeBitmap = has_bitmap_strike(typeface, range);
axisAlignedBitmap = is_axis_aligned(fRec);
}
// If the user requested aliased, do so with aliased compatible metrics.
if (SkMask::kBW_Format == fRec.fMaskFormat) {
fTextSizeRender = gdiTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_ALIASED;
fTextureType = DWRITE_TEXTURE_ALIASED_1x1;
fTextSizeMeasure = gdiTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
// If we can use a bitmap, use gdi classic rendering and measurement.
// This will not always provide a bitmap, but matches expected behavior.
} else if (treatLikeBitmap && axisAlignedBitmap) {
fTextSizeRender = gdiTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_GDI_CLASSIC;
fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
fTextSizeMeasure = gdiTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
// If rotated but the horizontal text could have used a bitmap,
// render high quality rotated glyphs but measure using bitmap metrics.
} else if (treatLikeBitmap) {
fTextSizeRender = gdiTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
fTextSizeMeasure = gdiTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
// Fonts that have hints but no gasp table get non-symmetric rendering.
// Usually such fonts have low quality hints which were never tested
// with anything but GDI ClearType classic. Such fonts often rely on
// drop out control in the y direction in order to be legible.
} else if (is_hinted_without_gasp(typeface)) {
fTextSizeRender = gdiTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL;
fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
fTextSizeMeasure = realTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
// The normal case is to use natural symmetric rendering and linear metrics.
} else {
fTextSizeRender = realTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
fTextSizeMeasure = realTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
}
if (this->isSubpixel()) {
fTextSizeMeasure = realTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
}
}
SkScalerContext_DW::SkScalerContext_DW(DWriteFontTypeface* typeface,
const SkDescriptor* desc)
: SkScalerContext(typeface, desc)
, fTypeface(SkRef(typeface))
, fGlyphCount(-1) {
// In general, all glyphs should use CLEARTYPE_NATURAL_SYMMETRIC
// except when bi-level rendering is requested or there are embedded
// bi-level bitmaps (and the embedded bitmap flag is set and no rotation).
//
// DirectWrite's IDWriteFontFace::GetRecommendedRenderingMode does not do
// this. As a result, determine the actual size of the text and then see if
// there are any embedded bi-level bitmaps of that size. If there are, then
// force bitmaps by requesting bi-level rendering.
//
// FreeType allows for separate ppemX and ppemY, but DirectWrite assumes
// square pixels and only uses ppemY. Therefore the transform must track any
// non-uniform x-scale.
//
// Also, rotated glyphs should have the same absolute advance widths as
// horizontal glyphs and the subpixel flag should not affect glyph shapes.
// A is the total matrix.
SkMatrix A;
fRec.getSingleMatrix(&A);
// h is where A maps the horizontal baseline.
SkPoint h = SkPoint::Make(SK_Scalar1, 0);
A.mapPoints(&h, 1);
// G is the Givens Matrix for A (rotational matrix where GA[0][1] == 0).
SkMatrix G;
SkComputeGivensRotation(h, &G);
// GA is the matrix A with rotation removed.
SkMatrix GA(G);
GA.preConcat(A);
// realTextSize is the actual device size we want (as opposed to the size the user requested).
// gdiTextSize is the size we request when GDI compatible.
// If the scale is negative, this means the matrix will do the flip anyway.
SkScalar realTextSize = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
// Due to floating point math, the lower bits are suspect. Round carefully.
SkScalar gdiTextSize = SkScalarRoundToScalar(realTextSize * 64.0f) / 64.0f;
if (gdiTextSize == 0) {
gdiTextSize = SK_Scalar1;
}
bool bitmapRequested = SkToBool(fRec.fFlags & SkScalerContext::kEmbeddedBitmapText_Flag);
bool treatLikeBitmap = false;
bool axisAlignedBitmap = false;
if (bitmapRequested) {
// When embedded bitmaps are requested, treat the entire range like
// a bitmap strike if the range is gridfit only and contains a bitmap.
int bitmapPPEM = SkScalarTruncToInt(gdiTextSize);
PPEMRange range = { bitmapPPEM, bitmapPPEM };
expand_range_if_gridfit_only(typeface, bitmapPPEM, &range);
treatLikeBitmap = has_bitmap_strike(typeface, range);
axisAlignedBitmap = is_axis_aligned(fRec);
}
// If the user requested aliased, do so with aliased compatible metrics.
if (SkMask::kBW_Format == fRec.fMaskFormat) {
fTextSizeRender = gdiTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_ALIASED;
fTextureType = DWRITE_TEXTURE_ALIASED_1x1;
fTextSizeMeasure = gdiTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
// If we can use a bitmap, use gdi classic rendering and measurement.
// This will not always provide a bitmap, but matches expected behavior.
} else if (treatLikeBitmap && axisAlignedBitmap) {
fTextSizeRender = gdiTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_GDI_CLASSIC;
fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
fTextSizeMeasure = gdiTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
// If rotated but the horizontal text could have used a bitmap,
// render high quality rotated glyphs but measure using bitmap metrics.
} else if (treatLikeBitmap) {
fTextSizeRender = gdiTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
fTextSizeMeasure = gdiTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;
// Fonts that have hints but no gasp table get non-symmetric rendering.
// Usually such fonts have low quality hints which were never tested
// with anything but GDI ClearType classic. Such fonts often rely on
// drop out control in the y direction in order to be legible.
} else if (is_hinted_without_gasp(typeface)) {
fTextSizeRender = gdiTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL;
fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
fTextSizeMeasure = realTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
// The normal case is to use natural symmetric rendering and linear metrics.
} else {
fTextSizeRender = realTextSize;
fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
fTextSizeMeasure = realTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
}
if (this->isSubpixel()) {
fTextSizeMeasure = realTextSize;
fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
}
// Remove the realTextSize, as that is the text height scale currently in A.
SkScalar scale = SkScalarInvert(realTextSize);
// fSkXform is the total matrix A without the text height scale.
fSkXform = A;
fSkXform.preScale(scale, scale); //remove the text height scale.
fXform.m11 = SkScalarToFloat(fSkXform.getScaleX());
fXform.m12 = SkScalarToFloat(fSkXform.getSkewY());
fXform.m21 = SkScalarToFloat(fSkXform.getSkewX());
fXform.m22 = SkScalarToFloat(fSkXform.getScaleY());
fXform.dx = 0;
fXform.dy = 0;
// GsA is the non-rotational part of A without the text height scale.
SkMatrix GsA(GA);
GsA.preScale(scale, scale); //remove text height scale, G is rotational so reorders with scale.
fGsA.m11 = SkScalarToFloat(GsA.get(SkMatrix::kMScaleX));
fGsA.m12 = SkScalarToFloat(GsA.get(SkMatrix::kMSkewY)); // This should be ~0.
fGsA.m21 = SkScalarToFloat(GsA.get(SkMatrix::kMSkewX));
fGsA.m22 = SkScalarToFloat(GsA.get(SkMatrix::kMScaleY));
fGsA.dx = 0;
fGsA.dy = 0;
// fG_inv is G inverse, which is fairly simple since G is 2x2 rotational.
fG_inv.setAll(G.get(SkMatrix::kMScaleX), -G.get(SkMatrix::kMSkewX), G.get(SkMatrix::kMTransX),
-G.get(SkMatrix::kMSkewY), G.get(SkMatrix::kMScaleY), G.get(SkMatrix::kMTransY),
G.get(SkMatrix::kMPersp0), G.get(SkMatrix::kMPersp1), G.get(SkMatrix::kMPersp2));
}