Unicode line-breaking.

docs/docs/02-changelog.md

@@ -3,6 +3,10 @@ import Video from '@site/src/components/Video';
 
 # Changelog
 
+## 21.1.4 (Minecraft 1.21.1)
+
+- Switch to Unicode line-breaking to improve breaking long lines for Chinese, Japanese, Korean, and other languages.
+
 ## 21.1.3 (Minecraft 1.21.1)
 
 - Disable superfluous tracing code slowing down startup.

src/main/java/guideme/internal/screen/GuideNavBar.java

@@ -131,10 +131,12 @@ public void renderWidget(GuiGraphics graphics, int mouseX, int mouseY, float par
             return; // do not render the navbar if there are no nodes.
         }
 
-        updateLayout();
-
         widthTransition.update();
 
+        if (state != State.CLOSED) {
+            updateLayout();
+        }
+
         var renderContext = new SimpleRenderContext(graphics);
 
         double currentTime = GLFW.glfwGetTime();

src/main/java/guideme/layout/flow/LineBuilder.java

@@ -11,6 +11,7 @@
 import guideme.layout.LayoutContext;
 import guideme.style.ResolvedTextStyle;
 import guideme.style.TextAlignment;
+import java.text.BreakIterator;
 import java.util.List;
 import java.util.function.Consumer;
 import org.jetbrains.annotations.Nullable;
@@ -202,18 +203,13 @@ private void appendText(String text, LytFlowContent flowContent) {
     }
 
     private void iterateRuns(CharSequence text, ResolvedTextStyle style, char lastChar, LineConsumer consumer) {
-        int lastBreakOpportunity = -1;
-        float widthAtBreakOpportunity = 0;
         float curLineWidth = 0;
 
         var fontScale = style.fontScale();
         var lineBuffer = new StringBuilder();
 
         boolean lastCharWasWhitespace = Character.isWhitespace(lastChar);
-        // When starting after a whitespace on an existing line, we have a break opportunity at the start
-        if (lastCharWasWhitespace) {
-            lastBreakOpportunity = 0;
-        }
+        boolean canBreakAtStart = lastCharWasWhitespace;
 
         for (var i = 0; i < text.length(); i++) {
             char ch = text.charAt(i);
@@ -236,8 +232,6 @@ private void iterateRuns(CharSequence text, ResolvedTextStyle style, char lastCh
                 } else {
                     consumer.visitRun(lineBuffer, curLineWidth, true);
                     lineBuffer.setLength(0);
-                    widthAtBreakOpportunity = curLineWidth = 0;
-                    lastBreakOpportunity = 0;
                     lastCharWasWhitespace = true;
                     remainingLineWidth = getAvailableHorizontalSpace();
                     continue;
@@ -249,9 +243,6 @@ private void iterateRuns(CharSequence text, ResolvedTextStyle style, char lastCh
                 if (lastCharWasWhitespace && style.whiteSpace().isCollapseWhitespace()) {
                     continue; // White space collapsing
                 }
-                // Treat spaces as a safe-point for going back to when needing to line-break later
-                lastBreakOpportunity = lineBuffer.length();
-                widthAtBreakOpportunity = curLineWidth;
                 lastCharWasWhitespace = true;
             } else {
                 lastCharWasWhitespace = false;
@@ -260,12 +251,32 @@ private void iterateRuns(CharSequence text, ResolvedTextStyle style, char lastCh
             var advance = context.getAdvance(codePoint, style) * fontScale;
             // Break line if necessary
             if (curLineWidth + advance > remainingLineWidth) {
-                // If we had a break opportunity, use it
-                // In this scenario, the space itself is discarded
-                if (lastBreakOpportunity != -1) {
-                    consumer.visitRun(lineBuffer.subSequence(0, lastBreakOpportunity), widthAtBreakOpportunity, true);
+                int precedingBreakOpportunity;
+
+                // BreakIterator will only ever break *AFTER* whitespace, but since we ignore the last break opportunity
+                // we need to also ignore that...
+                if (lastCharWasWhitespace) {
+                    precedingBreakOpportunity = lineBuffer.length();
+                } else {
+                    // Find break opportunities and include the current character in it.
+                    var breakIterator = BreakIterator.getLineInstance();
+                    breakIterator.setText(lineBuffer.toString() + (char) codePoint);
+                    precedingBreakOpportunity = breakIterator.preceding(lineBuffer.length() + 1);
+                }
+
+                // If the preceding text chunk ended on a whitespace, we can break there if the
+                // current word does not offer us any opportunity to.
+                if (precedingBreakOpportunity > 0 || precedingBreakOpportunity == 0 && canBreakAtStart) {
+                    // Determine width up until the break opportunity.
+                    var widthAtBreakOpportunity = 0f;
+                    for (var j = 0; j < precedingBreakOpportunity; j++) {
+                        widthAtBreakOpportunity += context.getAdvance(lineBuffer.charAt(j), style) * fontScale;
+                    }
+
+                    consumer.visitRun(lineBuffer.subSequence(0, precedingBreakOpportunity), widthAtBreakOpportunity,
+                            true);
                     curLineWidth -= widthAtBreakOpportunity;
-                    lineBuffer.delete(0, lastBreakOpportunity);
+                    lineBuffer.delete(0, precedingBreakOpportunity);
                     if (!lineBuffer.isEmpty() && Character.isWhitespace(lineBuffer.charAt(0))) {
                         var firstChar = lineBuffer.charAt(0);
                         lineBuffer.deleteCharAt(0);
@@ -278,8 +289,6 @@ private void iterateRuns(CharSequence text, ResolvedTextStyle style, char lastCh
                     lineBuffer.setLength(0);
                     curLineWidth = 0;
                 }
-                lastBreakOpportunity = 0;
-                widthAtBreakOpportunity = curLineWidth;
                 remainingLineWidth = getAvailableHorizontalSpace();
                 // If a white-space character broke the line, ignore it as it
                 // would otherwise be at the start of the next line

src/test/java/guideme/layout/flow/LineBuilderTest.java

@@ -30,7 +30,7 @@ void dontBreakInWords() {
         var lines = getLines(3, "A BC");
 
         assertThat(lines).extracting(this::getTextContent).containsExactly(
-                "A",
+                "A ",
                 "BC");
     }
 
@@ -57,6 +57,17 @@ void testWhitespaceCollapsing() {
                 "A B");
     }
 
+    /**
+     * Consider CJK characters as break opportunities and don't fall back to the last whitespace in mixed language text.
+     */
+    @Test
+    void testBreakBetweenCJKCharacters() {
+        var lines = getLines(5, "A Bを変更す");
+
+        assertThat(lines).extracting(this::getTextContent).containsExactly(
+                "A Bを変", "更す");
+    }
+
     private static ArrayList<Line> getLines(int charsPerLine, String... textChunks) {
         var lines = new ArrayList<Line>();
         var floats = new ArrayList<LineBlock>();

src/testmod/resources/assets/testmod/guides/testmod/guide/index.md

@@ -5,6 +5,8 @@ item_ids:
 
 # Start Page
 
+[Japanese](./japanese.md)
+
 [Markdown](./markdown.md)
 
 Welcome to the world of <ItemImage id="minecraft:stone" />

src/testmod/resources/assets/testmod/guides/testmod/guide/japanese.md

@@ -0,0 +1,8 @@
+---
+navigation:
+  title: チャンネル
+---
+
+# チャンネル
+
+マインクラフト1.18用のAE2 10.0.0では、ワールド内でのAE2チャンネルの動作を変更する新しいオプションが導入されています。