core/jni/android/graphics/TextLayout.cpp - platform/frameworks/base - Gitiles

 /*
  * 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,SkCanvas *canvas, SkPath *path) {
     sp<TextLayoutCacheValue> value;
 #if USE_TEXT_LAYOUT_CACHE
     // Return advances from the cache. Compute them if needed
     value = TextLayoutCache::getInstance().getValue(paint, text, 0, len,
             len, bidiFlags);
 #else
     value = new TextLayoutCacheValue(len);
     TextLayoutEngine::getInstance().computeValues(value.get(), paint,
             reinterpret_cast<const UChar*>(text), 0, len, len, bidiFlags);
 #endif
     if (value == NULL) {
         LOGE("Cannot get TextLayoutCache value for text = '%s'",
                 String8(text, len).string());
         return ;
     }
     SkScalar x_ = SkFloatToScalar(x);
     SkScalar y_ = SkFloatToScalar(y);
     if (canvas) {
         canvas->drawText(value->getGlyphs(), value->getGlyphsCount() * 2, x_, y_, *paint);
     } else {
         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<TextLayoutCacheValue> value;
 #if USE_TEXT_LAYOUT_CACHE
     // Return advances from the cache. Compute them if needed
     value = TextLayoutCache::getInstance().getValue(paint, chars, start, count,
             contextCount, dirFlags);
 #else
     value = new TextLayoutCacheValue(contextCount);
     TextLayoutEngine::getInstance().computeValues(value.get(), paint,
             reinterpret_cast<const UChar*>(chars), start, count, contextCount, dirFlags);
 #endif
     if (value == NULL) {
         LOGE("Cannot get TextLayoutCache value for text = '%s'",
                 String8(chars + start, count).string());
         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, NULL, 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);

     if (!needsLayout(text, count, bidiFlags)) {
         canvas->drawTextOnPathHV(text, count << 1, *path, h_, v_, *paint);
         return;
     }

     sp<TextLayoutCacheValue> value;
 #if USE_TEXT_LAYOUT_CACHE
     value = TextLayoutCache::getInstance().getValue(paint, text, 0, count,
             count, bidiFlags);
 #else
     value = new TextLayoutCacheValue(count);
     TextLayoutEngine::getInstance().computeValues(value.get(), paint,
             reinterpret_cast<const UChar*>(text), 0, count, count, bidiFlags);
 #endif
     if (value == NULL) {
         LOGE("Cannot get TextLayoutCache value for text = '%s'",
                 String8(text, count).string());
         return ;
     }

     // Save old text encoding
     SkPaint::TextEncoding oldEncoding = paint->getTextEncoding();
     // Define Glyph encoding
     paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);

     canvas->drawTextOnPathHV(value->getGlyphs(), value->getGlyphsCount() * 2, *path, h_, v_, *paint);

     // Get back old encoding
     paint->setTextEncoding(oldEncoding);
 }

 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
     LOGD("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
             LOGD("icu-adv = %f - total = %f", outAdvances[i], totalAdvance);
 #endif
         }
     } else {
 #if DEBUG_ADVANCES
     LOGD("ICU -- count=%d", count);
 #endif
         for (size_t i = 0; i < count; i++) {
             totalAdvance += outAdvances[i] = SkScalarToFloat(scalarArray[i]);
 #if DEBUG_ADVANCES
             LOGD("icu-adv = %f - total = %f", outAdvances[i], totalAdvance);
 #endif
         }
     }
     *outTotalAdvance = totalAdvance;
 }

 }
	/*
	* 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,SkCanvas canvas, SkPath path) {
	sp<TextLayoutCacheValue> value;
	#if USE_TEXT_LAYOUT_CACHE
	// Return advances from the cache. Compute them if needed
	value = TextLayoutCache::getInstance().getValue(paint, text, 0, len,
	len, bidiFlags);
	#else
	value = new TextLayoutCacheValue(len);
	TextLayoutEngine::getInstance().computeValues(value.get(), paint,
	reinterpret_cast<const UChar*>(text), 0, len, len, bidiFlags);
	#endif
	if (value == NULL) {
	LOGE("Cannot get TextLayoutCache value for text = '%s'",
	String8(text, len).string());
	return ;
	}
	SkScalar x_ = SkFloatToScalar(x);
	SkScalar y_ = SkFloatToScalar(y);
	if (canvas) {
	canvas->drawText(value->getGlyphs(), value->getGlyphsCount() * 2, x_, y_, *paint);
	} else {
	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<TextLayoutCacheValue> value;
	#if USE_TEXT_LAYOUT_CACHE
	// Return advances from the cache. Compute them if needed
	value = TextLayoutCache::getInstance().getValue(paint, chars, start, count,
	contextCount, dirFlags);
	#else
	value = new TextLayoutCacheValue(contextCount);
	TextLayoutEngine::getInstance().computeValues(value.get(), paint,
	reinterpret_cast<const UChar*>(chars), start, count, contextCount, dirFlags);
	#endif
	if (value == NULL) {
	LOGE("Cannot get TextLayoutCache value for text = '%s'",
	String8(chars + start, count).string());
	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, NULL, 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);

	if (!needsLayout(text, count, bidiFlags)) {
	canvas->drawTextOnPathHV(text, count << 1, path, h_, v_, paint);
	return;
	}

	sp<TextLayoutCacheValue> value;
	#if USE_TEXT_LAYOUT_CACHE
	value = TextLayoutCache::getInstance().getValue(paint, text, 0, count,
	count, bidiFlags);
	#else
	value = new TextLayoutCacheValue(count);
	TextLayoutEngine::getInstance().computeValues(value.get(), paint,
	reinterpret_cast<const UChar*>(text), 0, count, count, bidiFlags);
	#endif
	if (value == NULL) {
	LOGE("Cannot get TextLayoutCache value for text = '%s'",
	String8(text, count).string());
	return ;
	}

	// Save old text encoding
	SkPaint::TextEncoding oldEncoding = paint->getTextEncoding();
	// Define Glyph encoding
	paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);

	canvas->drawTextOnPathHV(value->getGlyphs(), value->getGlyphsCount() * 2, path, h_, v_, paint);

	// Get back old encoding
	paint->setTextEncoding(oldEncoding);
	}

	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
	LOGD("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
	LOGD("icu-adv = %f - total = %f", outAdvances[i], totalAdvance);
	#endif
	}
	} else {
	#if DEBUG_ADVANCES
	LOGD("ICU -- count=%d", count);
	#endif
	for (size_t i = 0; i < count; i++) {
	totalAdvance += outAdvances[i] = SkScalarToFloat(scalarArray[i]);
	#if DEBUG_ADVANCES
	LOGD("icu-adv = %f - total = %f", outAdvances[i], totalAdvance);
	#endif
	}
	}
	*outTotalAdvance = totalAdvance;
	}

	}