Add TextShaper API

TextShaper API provides a primitive text layout result, e.g. what glyph is used etc.

Here is the new APIs and its description

- PositionedGlyphs
This is a native instance backed object that gives layout information to developers.

- GlyphStyle
The glyph style is an object that holds the parameters that will be used for drawing.
This object is a subset of the Paint object for avoiding creating lots of Paint copy.

- TextShaper#shapeText
This does a text shaping and gives TextShaper.Result. This is a native backed primitive
shaping API.

- StyledTextShaper
This is a text shaper for a styled text. This will be the top-level developer facing
API for shaping text.

Bug: 168048923
Test: atest FontTest TextShaperTest StyledTextShaperTest
Change-Id: I2e91d1ef8503b25b28efc94da7de7cad49c4c1a9
diff --git a/libs/hwui/jni/text/TextShaper.cpp b/libs/hwui/jni/text/TextShaper.cpp
new file mode 100644
index 0000000..9d9e91f
--- /dev/null
+++ b/libs/hwui/jni/text/TextShaper.cpp
@@ -0,0 +1,206 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "TextShaper"
+
+#include "graphics_jni_helpers.h"
+#include <nativehelper/ScopedStringChars.h>
+#include <nativehelper/ScopedPrimitiveArray.h>
+#include <set>
+#include <algorithm>
+
+#include "SkPaint.h"
+#include "SkTypeface.h"
+#include <hwui/MinikinSkia.h>
+#include <hwui/MinikinUtils.h>
+#include <hwui/Paint.h>
+#include <minikin/MinikinPaint.h>
+#include <minikin/MinikinFont.h>
+
+namespace android {
+
+struct LayoutWrapper {
+    LayoutWrapper(minikin::Layout&& layout, float ascent, float descent)
+        : layout(std::move(layout)), ascent(ascent), descent(descent)  {}
+    minikin::Layout layout;
+    float ascent;
+    float descent;
+};
+
+static void releaseLayout(jlong ptr) {
+    delete reinterpret_cast<LayoutWrapper*>(ptr);
+}
+
+static jlong shapeTextRun(const uint16_t* text, int textSize, int start, int count,
+    int contextStart, int contextCount, minikin::Bidi bidiFlags,
+    const Paint& paint, const Typeface* typeface) {
+
+    minikin::MinikinPaint minikinPaint = MinikinUtils::prepareMinikinPaint(&paint, typeface);
+
+    minikin::Layout layout = MinikinUtils::doLayout(&paint, bidiFlags, typeface,
+        text, textSize, start, count, contextStart, contextCount, nullptr);
+
+    std::set<const minikin::Font*> seenFonts;
+    float overallAscent = 0;
+    float overallDescent = 0;
+    for (int i = 0; i < layout.nGlyphs(); ++i) {
+        const minikin::Font* font = layout.getFont(i);
+        if (seenFonts.find(font) != seenFonts.end()) continue;
+        minikin::MinikinExtent extent = {};
+        font->typeface()->GetFontExtent(&extent, minikinPaint, layout.getFakery(i));
+        overallAscent = std::min(overallAscent, extent.ascent);
+        overallDescent = std::max(overallDescent, extent.descent);
+    }
+
+    std::unique_ptr<LayoutWrapper> ptr = std::make_unique<LayoutWrapper>(
+        std::move(layout), overallAscent, overallDescent
+    );
+
+    return reinterpret_cast<jlong>(ptr.release());
+}
+
+static jlong TextShaper_shapeTextRunChars(JNIEnv *env, jobject, jcharArray charArray,
+    jint start, jint count, jint contextStart, jint contextCount, jboolean isRtl,
+    jlong paintPtr) {
+    ScopedCharArrayRO text(env, charArray);
+    Paint* paint = reinterpret_cast<Paint*>(paintPtr);
+    const Typeface* typeface = paint->getAndroidTypeface();
+    const minikin::Bidi bidiFlags = isRtl ? minikin::Bidi::FORCE_RTL : minikin::Bidi::FORCE_LTR;
+    return shapeTextRun(
+        text.get(), text.size(),
+        start, count,
+        contextStart, contextCount,
+        bidiFlags,
+        *paint, typeface);
+
+}
+
+static jlong TextShaper_shapeTextRunString(JNIEnv *env, jobject, jstring string,
+    jint start, jint count, jint contextStart, jint contextCount, jboolean isRtl,
+    jlong paintPtr) {
+    ScopedStringChars text(env, string);
+    Paint* paint = reinterpret_cast<Paint*>(paintPtr);
+    const Typeface* typeface = paint->getAndroidTypeface();
+    const minikin::Bidi bidiFlags = isRtl ? minikin::Bidi::FORCE_RTL : minikin::Bidi::FORCE_LTR;
+    return shapeTextRun(
+        text.get(), text.size(),
+        start, count,
+        contextStart, contextCount,
+        bidiFlags,
+        *paint, typeface);
+}
+
+// CriticalNative
+static jint TextShaper_Result_getGlyphCount(CRITICAL_JNI_PARAMS_COMMA jlong ptr) {
+    const LayoutWrapper* layout = reinterpret_cast<LayoutWrapper*>(ptr);
+    return layout->layout.nGlyphs();
+}
+
+// CriticalNative
+static jfloat TextShaper_Result_getTotalAdvance(CRITICAL_JNI_PARAMS_COMMA jlong ptr) {
+    const LayoutWrapper* layout = reinterpret_cast<LayoutWrapper*>(ptr);
+    return layout->layout.getAdvance();
+}
+
+// CriticalNative
+static jfloat TextShaper_Result_getAscent(CRITICAL_JNI_PARAMS_COMMA jlong ptr) {
+    const LayoutWrapper* layout = reinterpret_cast<LayoutWrapper*>(ptr);
+    return layout->ascent;
+}
+
+// CriticalNative
+static jfloat TextShaper_Result_getDescent(CRITICAL_JNI_PARAMS_COMMA jlong ptr) {
+    const LayoutWrapper* layout = reinterpret_cast<LayoutWrapper*>(ptr);
+    return layout->descent;
+}
+
+// CriticalNative
+static jint TextShaper_Result_getGlyphId(CRITICAL_JNI_PARAMS_COMMA jlong ptr, jint i) {
+    const LayoutWrapper* layout = reinterpret_cast<LayoutWrapper*>(ptr);
+    return layout->layout.getGlyphId(i);
+}
+
+// CriticalNative
+static jfloat TextShaper_Result_getX(CRITICAL_JNI_PARAMS_COMMA jlong ptr, jint i) {
+    const LayoutWrapper* layout = reinterpret_cast<LayoutWrapper*>(ptr);
+    return layout->layout.getX(i);
+}
+
+// CriticalNative
+static jfloat TextShaper_Result_getY(CRITICAL_JNI_PARAMS_COMMA jlong ptr, jint i) {
+    const LayoutWrapper* layout = reinterpret_cast<LayoutWrapper*>(ptr);
+    return layout->layout.getY(i);
+}
+
+// CriticalNative
+static jlong TextShaper_Result_getFont(CRITICAL_JNI_PARAMS_COMMA jlong ptr, jint i) {
+    const LayoutWrapper* layout = reinterpret_cast<LayoutWrapper*>(ptr);
+    return reinterpret_cast<jlong>(layout->layout.getFont(i));
+}
+
+// CriticalNative
+static jlong TextShaper_Result_nReleaseFunc(CRITICAL_JNI_PARAMS) {
+    return reinterpret_cast<jlong>(releaseLayout);
+}
+
+static const JNINativeMethod gMethods[] = {
+    // Fast Natives
+    {"nativeShapeTextRun", "("
+        "[C"  // text
+        "I"  // start
+        "I"  // count
+        "I"  // contextStart
+        "I"  // contextCount
+        "Z"  // isRtl
+        "J)"  // paint
+        "J",  // LayoutPtr
+        (void*) TextShaper_shapeTextRunChars},
+
+    {"nativeShapeTextRun", "("
+        "Ljava/lang/String;"  // text
+        "I"  // start
+        "I"  // count
+        "I"  // contextStart
+        "I"  // contextCount
+        "Z"  // isRtl
+        "J)"  // paint
+        "J",  // LayoutPtr
+        (void*) TextShaper_shapeTextRunString},
+
+};
+
+static const JNINativeMethod gResultMethods[] = {
+    { "nGetGlyphCount", "(J)I", (void*)TextShaper_Result_getGlyphCount },
+    { "nGetTotalAdvance", "(J)F", (void*)TextShaper_Result_getTotalAdvance },
+    { "nGetAscent", "(J)F", (void*)TextShaper_Result_getAscent },
+    { "nGetDescent", "(J)F", (void*)TextShaper_Result_getDescent },
+    { "nGetGlyphId", "(JI)I", (void*)TextShaper_Result_getGlyphId },
+    { "nGetX", "(JI)F", (void*)TextShaper_Result_getX },
+    { "nGetY", "(JI)F", (void*)TextShaper_Result_getY },
+    { "nGetFont", "(JI)J", (void*)TextShaper_Result_getFont },
+    { "nReleaseFunc", "()J", (void*)TextShaper_Result_nReleaseFunc },
+};
+
+int register_android_graphics_text_TextShaper(JNIEnv* env) {
+    return RegisterMethodsOrDie(env, "android/graphics/text/TextShaper", gMethods,
+                                NELEM(gMethods))
+        + RegisterMethodsOrDie(env, "android/graphics/text/PositionedGlyphs",
+            gResultMethods, NELEM(gResultMethods));
+}
+
+}
+