| /* |
| * Copyright (C) 2010 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "TextLayout" |
| |
| #include "TextLayout.h" |
| #include "TextLayoutCache.h" |
| |
| #include <android_runtime/AndroidRuntime.h> |
| |
| #include "SkTemplates.h" |
| #include "unicode/ubidi.h" |
| #include "unicode/ushape.h" |
| #include <utils/Log.h> |
| |
| namespace android { |
| |
| // Returns true if we might need layout. If bidiFlags force LTR, assume no layout, if |
| // bidiFlags indicate there probably is RTL, assume we do, otherwise scan the text |
| // looking for a character >= the first RTL character in unicode and assume we do if |
| // we find one. |
| bool TextLayout::needsLayout(const jchar* text, jint len, jint bidiFlags) { |
| if (bidiFlags == kBidi_Force_LTR) { |
| return false; |
| } |
| if ((bidiFlags == kBidi_RTL) || (bidiFlags == kBidi_Default_RTL) || |
| bidiFlags == kBidi_Force_RTL) { |
| return true; |
| } |
| for (int i = 0; i < len; ++i) { |
| if (text[i] >= UNICODE_FIRST_RTL_CHAR) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Draws or gets the path of a paragraph of text on a single line, running bidi and shaping. |
| // This will draw if canvas is not null, otherwise path must be non-null and it will create |
| // a path representing the text that would have been drawn. |
| void TextLayout::handleText(SkPaint *paint, const jchar* text, jsize len, |
| jint bidiFlags, jfloat x, jfloat y, SkPath *path) { |
| sp<TextLayoutValue> value = TextLayoutEngine::getInstance().getValue(paint, |
| text, 0, len, len, bidiFlags); |
| if (value == NULL) { |
| return ; |
| } |
| SkScalar x_ = SkFloatToScalar(x); |
| SkScalar y_ = SkFloatToScalar(y); |
| // Beware: this needs Glyph encoding (already done on the Paint constructor) |
| paint->getTextPath(value->getGlyphs(), value->getGlyphsCount() * 2, x_, y_, path); |
| } |
| |
| void TextLayout::getTextRunAdvances(SkPaint* paint, const jchar* chars, jint start, |
| jint count, jint contextCount, jint dirFlags, |
| jfloat* resultAdvances, jfloat* resultTotalAdvance) { |
| sp<TextLayoutValue> value = TextLayoutEngine::getInstance().getValue(paint, |
| chars, start, count, contextCount, dirFlags); |
| if (value == NULL) { |
| return ; |
| } |
| if (resultAdvances) { |
| memcpy(resultAdvances, value->getAdvances(), value->getAdvancesCount() * sizeof(jfloat)); |
| } |
| if (resultTotalAdvance) { |
| *resultTotalAdvance = value->getTotalAdvance(); |
| } |
| } |
| |
| void TextLayout::getTextRunAdvancesICU(SkPaint* paint, const jchar* chars, jint start, |
| jint count, jint contextCount, jint dirFlags, |
| jfloat* resultAdvances, jfloat& resultTotalAdvance) { |
| // Compute advances and return them |
| computeAdvancesWithICU(paint, chars, start, count, contextCount, dirFlags, |
| resultAdvances, &resultTotalAdvance); |
| } |
| |
| void TextLayout::getTextPath(SkPaint *paint, const jchar *text, jsize len, |
| jint bidiFlags, jfloat x, jfloat y, SkPath *path) { |
| handleText(paint, text, len, bidiFlags, x, y, path); |
| } |
| |
| |
| void TextLayout::drawTextOnPath(SkPaint* paint, const jchar* text, int count, |
| int bidiFlags, jfloat hOffset, jfloat vOffset, |
| SkPath* path, SkCanvas* canvas) { |
| |
| SkScalar h_ = SkFloatToScalar(hOffset); |
| SkScalar v_ = SkFloatToScalar(vOffset); |
| |
| sp<TextLayoutValue> value = TextLayoutEngine::getInstance().getValue(paint, |
| text, 0, count, count, bidiFlags); |
| if (value == NULL) { |
| return; |
| } |
| |
| // Beware: this needs Glyph encoding (already done on the Paint constructor) |
| canvas->drawTextOnPathHV(value->getGlyphs(), value->getGlyphsCount() * 2, *path, h_, v_, *paint); |
| } |
| |
| void TextLayout::computeAdvancesWithICU(SkPaint* paint, const UChar* chars, |
| size_t start, size_t count, size_t contextCount, int dirFlags, |
| jfloat* outAdvances, jfloat* outTotalAdvance) { |
| SkAutoSTMalloc<CHAR_BUFFER_SIZE, jchar> tempBuffer(contextCount); |
| jchar* buffer = tempBuffer.get(); |
| SkScalar* scalarArray = (SkScalar*)outAdvances; |
| |
| // this is where we'd call harfbuzz |
| // for now we just use ushape.c |
| size_t widths; |
| const jchar* text; |
| if (dirFlags & 0x1) { // rtl, call arabic shaping in case |
| UErrorCode status = U_ZERO_ERROR; |
| // Use fixed length since we need to keep start and count valid |
| u_shapeArabic(chars, contextCount, buffer, contextCount, |
| U_SHAPE_LENGTH_FIXED_SPACES_NEAR | |
| U_SHAPE_TEXT_DIRECTION_LOGICAL | U_SHAPE_LETTERS_SHAPE | |
| U_SHAPE_X_LAMALEF_SUB_ALTERNATE, &status); |
| // we shouldn't fail unless there's an out of memory condition, |
| // in which case we're hosed anyway |
| for (int i = start, e = i + count; i < e; ++i) { |
| if (buffer[i] == UNICODE_NOT_A_CHAR) { |
| buffer[i] = UNICODE_ZWSP; // zero-width-space for skia |
| } |
| } |
| text = buffer + start; |
| widths = paint->getTextWidths(text, count << 1, scalarArray); |
| } else { |
| text = chars + start; |
| widths = paint->getTextWidths(text, count << 1, scalarArray); |
| } |
| |
| jfloat totalAdvance = 0; |
| if (widths < count) { |
| #if DEBUG_ADVANCES |
| ALOGD("ICU -- count=%d", widths); |
| #endif |
| // Skia operates on code points, not code units, so surrogate pairs return only |
| // one value. Expand the result so we have one value per UTF-16 code unit. |
| |
| // Note, skia's getTextWidth gets confused if it encounters a surrogate pair, |
| // leaving the remaining widths zero. Not nice. |
| for (size_t i = 0, p = 0; i < widths; ++i) { |
| totalAdvance += outAdvances[p++] = SkScalarToFloat(scalarArray[i]); |
| if (p < count && |
| text[p] >= UNICODE_FIRST_LOW_SURROGATE && |
| text[p] < UNICODE_FIRST_PRIVATE_USE && |
| text[p-1] >= UNICODE_FIRST_HIGH_SURROGATE && |
| text[p-1] < UNICODE_FIRST_LOW_SURROGATE) { |
| outAdvances[p++] = 0; |
| } |
| #if DEBUG_ADVANCES |
| ALOGD("icu-adv = %f - total = %f", outAdvances[i], totalAdvance); |
| #endif |
| } |
| } else { |
| #if DEBUG_ADVANCES |
| ALOGD("ICU -- count=%d", count); |
| #endif |
| for (size_t i = 0; i < count; i++) { |
| totalAdvance += outAdvances[i] = SkScalarToFloat(scalarArray[i]); |
| #if DEBUG_ADVANCES |
| ALOGD("icu-adv = %f - total = %f", outAdvances[i], totalAdvance); |
| #endif |
| } |
| } |
| *outTotalAdvance = totalAdvance; |
| } |
| |
| } |