handle failure when creating a scalercontext
git-svn-id: http://skia.googlecode.com/svn/trunk@90 2bbb7eff-a529-9590-31e7-b0007b416f81
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reed@android.com
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d9c0f0b57a
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62900b4c64
@ -85,6 +85,12 @@ struct SkGlyph {
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size_t computeImageSize() const;
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/** Call this to set all of the metrics fields to 0 (e.g. if the scaler
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encounters an error measuring a glyph). Note: this does not alter the
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fImage, fPath, fID, fMaskFormat fields.
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*/
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void zeroMetrics();
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enum {
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kSubBits = 2,
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kSubMask = ((1 << kSubBits) - 1),
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@ -52,6 +52,19 @@ size_t SkGlyph::computeImageSize() const {
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return size;
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}
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void SkGlyph::zeroMetrics() {
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fAdvanceX = 0;
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fAdvanceY = 0;
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fWidth = 0;
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fHeight = 0;
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fTop = 0;
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fLeft = 0;
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fRsbDelta = 0;
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fLsbDelta = 0;
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}
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///////////////////////////////////////////////////////////////////////////////
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#ifdef SK_DEBUG
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#define DUMP_RECx
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#endif
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@ -521,10 +534,46 @@ void SkScalerContext::Rec::getSingleMatrix(SkMatrix* m) const
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}
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}
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///////////////////////////////////////////////////////////////////////////////
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#include "SkFontHost.h"
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class SkScalerContext_Empty : public SkScalerContext {
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public:
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SkScalerContext_Empty(const SkDescriptor* desc) : SkScalerContext(desc) {}
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protected:
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virtual unsigned generateGlyphCount() const {
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return 0;
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}
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virtual uint16_t generateCharToGlyph(SkUnichar uni) {
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return 0;
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}
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virtual void generateAdvance(SkGlyph* glyph) {
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glyph->zeroMetrics();
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}
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virtual void generateMetrics(SkGlyph* glyph) {
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glyph->zeroMetrics();
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}
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virtual void generateImage(const SkGlyph& glyph) {}
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virtual void generatePath(const SkGlyph& glyph, SkPath* path) {}
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virtual void generateFontMetrics(SkPaint::FontMetrics* mx,
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SkPaint::FontMetrics* my) {
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if (mx) {
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bzero(mx, sizeof(*mx));
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}
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if (my) {
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bzero(my, sizeof(*my));
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}
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}
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};
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SkScalerContext* SkScalerContext::Create(const SkDescriptor* desc)
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{
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return SkFontHost::CreateScalerContext(desc);
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SkScalerContext* c = SkFontHost::CreateScalerContext(desc);
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if (NULL == c) {
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c = SkNEW_ARGS(SkScalerContext_Empty, (desc));
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}
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return c;
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}
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@ -91,25 +91,62 @@ bool SkImageDecoder::allocPixelRef(SkBitmap* bitmap,
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///////////////////////////////////////////////////////////////////////////////
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/* Technically, this should be 342, since that is the cutoff point between
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an index and 32bit bitmap (they take equal ram), but since 32bit is almost
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always faster, I bump up the value a bit.
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*/
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#define MIN_SIZE_FOR_INDEX (512)
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/* Return the "optimal" config for this bitmap. In this case, we just look to
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promote index bitmaps to full-color, since those are a little faster to
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draw (fewer memory lookups).
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Seems like we could expose this to the caller through some exising or new
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proxy object, allowing them to decide (after sniffing some aspect of the
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original bitmap) what config they really want.
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*/
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static SkBitmap::Config optimal_config(const SkBitmap& bm,
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SkBitmap::Config pref) {
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if (bm.config() != pref) {
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if (bm.config() == SkBitmap::kIndex8_Config) {
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Sk64 size64 = bm.getSize64();
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if (size64.is32()) {
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int32_t size = size64.get32();
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if (size < MIN_SIZE_FOR_INDEX) {
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return SkBitmap::kARGB_8888_Config;
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}
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}
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}
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}
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return bm.config();
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}
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bool SkImageDecoder::decode(SkStream* stream, SkBitmap* bm,
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SkBitmap::Config pref, Mode mode) {
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// pass a temporary bitmap, so that if we return false, we are assured of
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// leaving the caller's bitmap untouched.
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SkBitmap tmp;
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// we reset this to false before calling onDecode
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fShouldCancelDecode = false;
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// pass a temporary bitmap, so that if we return false, we are assured of
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// leaving the caller's bitmap untouched.
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if (this->onDecode(stream, &tmp, pref, mode)) {
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/* We operate on a tmp bitmap until we know we succeed. This way
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we're sure we don't change the caller's bitmap and then later
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return false. Returning false must mean that their parameter
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is unchanged.
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*/
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bm->swap(tmp);
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return true;
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if (!this->onDecode(stream, &tmp, pref, mode)) {
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return false;
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}
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return false;
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SkBitmap::Config c = optimal_config(tmp, pref);
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if (c != tmp.config()) {
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if (mode == kDecodeBounds_Mode) {
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tmp.setConfig(c, tmp.width(), tmp.height());
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} else {
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SkBitmap tmp2;
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if (tmp.copyTo(&tmp2, c, this->getAllocator())) {
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tmp.swap(tmp2);
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}
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}
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}
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bm->swap(tmp);
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return true;
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}
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///////////////////////////////////////////////////////////////////////////////
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@ -63,6 +63,10 @@ class SkScalerContext_FreeType : public SkScalerContext {
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public:
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SkScalerContext_FreeType(const SkDescriptor* desc);
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virtual ~SkScalerContext_FreeType();
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bool success() const {
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return fFaceRec != NULL && fFTSize != NULL;
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}
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protected:
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virtual unsigned generateGlyphCount() const;
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@ -146,6 +150,7 @@ SkFaceRec::SkFaceRec(SkStream* strm, uint32_t fontID)
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fFTStream.close = sk_stream_close;
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}
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// Will return 0 on failure
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static SkFaceRec* ref_ft_face(uint32_t fontID) {
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SkFaceRec* rec = gFaceRecHead;
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while (rec) {
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@ -160,7 +165,6 @@ static SkFaceRec* ref_ft_face(uint32_t fontID) {
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SkStream* strm = SkFontHost::OpenStream(fontID);
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if (NULL == strm) {
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SkDEBUGF(("SkFontHost::OpenStream failed opening %x\n", fontID));
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sk_throw();
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return 0;
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}
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@ -187,7 +191,6 @@ static SkFaceRec* ref_ft_face(uint32_t fontID) {
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if (err) { // bad filename, try the default font
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fprintf(stderr, "ERROR: unable to open font '%x'\n", fontID);
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SkDELETE(rec);
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sk_throw();
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return 0;
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} else {
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SkASSERT(rec->fFace);
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@ -225,7 +228,7 @@ static void unref_ft_face(FT_Face face) {
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///////////////////////////////////////////////////////////////////////////
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SkScalerContext_FreeType::SkScalerContext_FreeType(const SkDescriptor* desc)
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: SkScalerContext(desc), fFTSize(NULL) {
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: SkScalerContext(desc) {
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SkAutoMutexAcquire ac(gFTMutex);
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FT_Error err;
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@ -238,8 +241,13 @@ SkScalerContext_FreeType::SkScalerContext_FreeType(const SkDescriptor* desc)
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++gFTCount;
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// load the font file
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fFTSize = NULL;
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fFace = NULL;
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fFaceRec = ref_ft_face(fRec.fFontID);
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fFace = fFaceRec ? fFaceRec->fFace : NULL;
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if (NULL == fFaceRec) {
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return;
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}
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fFace = fFaceRec->fFace;
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// compute our factors from the record
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@ -417,17 +425,6 @@ static FT_Pixel_Mode compute_pixel_mode(SkMask::Format format) {
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}
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}
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static void set_glyph_metrics_on_error(SkGlyph* glyph) {
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glyph->fRsbDelta = 0;
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glyph->fLsbDelta = 0;
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glyph->fWidth = 0;
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glyph->fHeight = 0;
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glyph->fTop = 0;
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glyph->fLeft = 0;
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glyph->fAdvanceX = 0;
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glyph->fAdvanceY = 0;
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}
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void SkScalerContext_FreeType::generateAdvance(SkGlyph* glyph) {
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#ifdef FT_ADVANCES_H
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/* unhinted and light hinted text have linearly scaled advances
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@ -437,7 +434,7 @@ void SkScalerContext_FreeType::generateAdvance(SkGlyph* glyph) {
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SkAutoMutexAcquire ac(gFTMutex);
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if (this->setupSize()) {
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set_glyph_metrics_on_error(glyph);
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glyph->zeroMetrics();
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return;
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}
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@ -478,7 +475,7 @@ void SkScalerContext_FreeType::generateMetrics(SkGlyph* glyph) {
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SkDEBUGF(("SkScalerContext_FreeType::generateMetrics(%x): FT_Load_Glyph(glyph:%d flags:%d) returned 0x%x\n",
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fFaceRec->fFontID, glyph->getGlyphID(fBaseGlyphCount), fLoadGlyphFlags, err));
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ERROR:
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set_glyph_metrics_on_error(glyph);
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glyph->zeroMetrics();
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return;
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}
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@ -769,7 +766,12 @@ void SkScalerContext_FreeType::generateFontMetrics(SkPaint::FontMetrics* mx,
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////////////////////////////////////////////////////////////////////////
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SkScalerContext* SkFontHost::CreateScalerContext(const SkDescriptor* desc) {
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return SkNEW_ARGS(SkScalerContext_FreeType, (desc));
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SkScalerContext_FreeType* c = SkNEW_ARGS(SkScalerContext_FreeType, (desc));
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if (!c->success()) {
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SkDELETE(c);
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c = NULL;
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}
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return c;
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}
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///////////////////////////////////////////////////////////////////////////////
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