void SkBaseDevice::drawTextRSXform(const void* text, size_t len,
const SkRSXform xform[], const SkPaint& paint) {
CountTextProc proc = nullptr;
switch (paint.getTextEncoding()) {
case SkPaint::kUTF8_TextEncoding:
proc = SkUTF8_CountUTF8Bytes;
break;
case SkPaint::kUTF16_TextEncoding:
proc = count_utf16;
break;
case SkPaint::kUTF32_TextEncoding:
proc = return_4;
break;
case SkPaint::kGlyphID_TextEncoding:
proc = return_2;
break;
}
SkPaint localPaint(paint);
SkShader* shader = paint.getShader();
SkMatrix localM, currM;
const void* stopText = (const char*)text + len;
while ((const char*)text < (const char*)stopText) {
localM.setRSXform(*xform++);
currM.setConcat(this->ctm(), localM);
SkAutoDeviceCTMRestore adc(this, currM);
// We want to rotate each glyph by the rsxform, but we don't want to rotate "space"
// (i.e. the shader that cares about the ctm) so we have to undo our little ctm trick
// with a localmatrixshader so that the shader draws as if there was no change to the ctm.
if (shader) {
SkMatrix inverse;
if (localM.invert(&inverse)) {
localPaint.setShader(shader->makeWithLocalMatrix(inverse));
} else {
localPaint.setShader(nullptr); // can't handle this xform
}
}
int subLen = proc((const char*)text);
this->drawText(text, subLen, 0, 0, localPaint);
text = (const char*)text + subLen;
}
}
