Fix line metrics per https://bugs.chromium.org/p/skia/issues/detail?id=12383 (#263)

skiko/src/jvmMain/cpp/common/paragraph/Paragraph.cc

@@ -134,10 +134,10 @@ extern "C" JNIEXPORT jobjectArray JNICALL Java_org_jetbrains_skia_paragraph_Para
     auto conv = skija::UtfIndicesConverter(*text);
     for (int i = 0; i < res.size(); ++i) {
         LineMetrics lm = res[i];
-        size_t startIndex = conv.from8To16(lm.fStartIndex);
-        size_t endExcludingWhitespaces = conv.from8To16(lm.fEndExcludingWhitespaces);
-        size_t endIndex = conv.from8To16(lm.fEndIndex);
-        size_t endIncludingNewline = conv.from8To16(lm.fEndIncludingNewline);
+        size_t startIndex = lm.fStartIndex;
+        size_t endExcludingWhitespaces = lm.fEndExcludingWhitespaces;
+        size_t endIndex = lm.fEndIndex;
+        size_t endIncludingNewline = lm.fEndIncludingNewline;
         jobject lmObj = env->NewObject(skija::paragraph::LineMetrics::cls, skija::paragraph::LineMetrics::ctor, startIndex, endIndex, endExcludingWhitespaces, endIncludingNewline, lm.fHardBreak, lm.fAscent, lm.fDescent, lm.fUnscaledAscent, lm.fHeight, lm.fWidth, lm.fLeft, lm.fBaseline, lm.fLineNumber);
         env->SetObjectArrayElement(resArray, i, lmObj);
         env->DeleteLocalRef(lmObj);

skiko/src/jvmTest/kotlin/org/jetbrains/skiko/ParagraphTest.kt

@@ -2,14 +2,43 @@ package org.jetbrains.skiko
 
 import org.jetbrains.skia.FontMgr
 import org.jetbrains.skia.FontStyle
-import org.jetbrains.skia.impl.NativePointer
 import org.jetbrains.skia.paragraph.FontCollection
+import org.jetbrains.skia.paragraph.LineMetrics
+import org.jetbrains.skia.paragraph.ParagraphBuilder
+import org.jetbrains.skia.paragraph.ParagraphStyle
+import org.junit.Assert.assertEquals
 import org.junit.Test
 
 class ParagraphTest {
+    private val fontCollection = FontCollection().setDefaultFontManager(FontMgr.default)
+
     @Test
     fun findTypefaces() {
-        val fontCollection = FontCollection().setDefaultFontManager(FontMgr.default)
         fontCollection.findTypefaces(emptyArray(), FontStyle.NORMAL)
     }
+
+    private fun singleLineMetrics(text: String): LineMetrics {
+        val style = ParagraphStyle()
+
+        return ParagraphBuilder(style, fontCollection).use {
+            it.addText(text)
+            it.build()
+        }.layout(Float.POSITIVE_INFINITY).lineMetrics.first()
+    }
+
+    @Test
+    fun layoutParagraph() {
+        singleLineMetrics("aa").let { lineMetrics -> // latin
+            assertEquals(0, lineMetrics.startIndex)
+            assertEquals(2, lineMetrics.endIndex)
+            assertEquals(2, lineMetrics.endIncludingNewline)
+            assertEquals(2, lineMetrics.endExcludingWhitespaces)
+        }
+        singleLineMetrics("яя").let { lineMetrics -> // cyrillic
+            assertEquals(0, lineMetrics.startIndex)
+            assertEquals(2, lineMetrics.endIndex)
+            assertEquals(2, lineMetrics.endIncludingNewline)
+            assertEquals(2, lineMetrics.endExcludingWhitespaces)
+        }
+    }
 }
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