[API] ImFontGlyphRangesBuilder and fonts example

Author: abvadabra

example/src/main/java/FontAwesomeIcons.java

@@ -1,12 +1,16 @@
-import imgui.ImGui;
-import imgui.ImGuiIO;
+import imgui.*;
 import imgui.app.Application;
 import imgui.app.Configuration;
 import imgui.extension.imnodes.ImNodes;
 import imgui.flag.ImGuiConfigFlags;
 import imgui.flag.ImGuiInputTextFlags;
 import imgui.type.ImString;
 
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
 public class Main extends Application {
     private final ImString str = new ImString(5);
     private final float[] flt = new float[1];
@@ -29,6 +33,34 @@ protected void initImGui(final Configuration config) {
         io.setConfigViewportsNoTaskBarIcon(true);
 
         ImNodes.createContext();
+
+        // Example of fonts configuration
+        // For more information read: https://github.com/ocornut/imgui/blob/33cdbe97b8fd233c6c12ca216e76398c2e89b0d8/docs/FONTS.md
+
+        io.getFonts().addFontDefault(); // Add default font for latin glyphs
+
+        // You can use the ImFontGlyphRangesBuilder helper to create glyph ranges based on text input.
+        // For example: for a game where your script is known, if you can feed your entire script to it (using addText) and only build the characters the game needs.
+        // Here we are using it just to combine all required glyphs in one place
+        final ImFontGlyphRangesBuilder rangesBuilder = new ImFontGlyphRangesBuilder(); // Glyphs ranges provide
+        rangesBuilder.addRanges(io.getFonts().getGlyphRangesDefault());
+        rangesBuilder.addRanges(io.getFonts().getGlyphRangesCyrillic());
+        rangesBuilder.addRanges(io.getFonts().getGlyphRangesJapanese());
+        rangesBuilder.addRanges(FontAwesomeIcons._IconRange);
+
+        // Font config for additional fonts
+        // This is a natively allocated struct so don't forget to call destroy after atlas is built
+        final ImFontConfig fontConfig = new ImFontConfig();
+        fontConfig.setMergeMode(true);  // Enable merge mode to merge cyrillic, japanese and icons with default font
+
+        final short[] glyphRanges = rangesBuilder.buildRanges();
+        io.getFonts().addFontFromMemoryTTF(loadFromResources("Tahoma.ttf"), 14, fontConfig, glyphRanges); // cyrillic glyphs
+        io.getFonts().addFontFromMemoryTTF(loadFromResources("NotoSansCJKjp-Medium.otf"), 14, fontConfig, glyphRanges); // japanese glyphs
+        io.getFonts().addFontFromMemoryTTF(loadFromResources("fa-regular-400.ttf"), 14, fontConfig, glyphRanges); // font awesome
+        io.getFonts().addFontFromMemoryTTF(loadFromResources("fa-solid-900.ttf"), 14, fontConfig, glyphRanges); // font awesome
+        io.getFonts().build();
+
+        fontConfig.destroy();
     }
 
     @Override
@@ -39,8 +71,8 @@ protected void disposeImGui() {
 
     @Override
     public void process() {
-        ImGui.text("Hello, World!");
-        if (ImGui.button("Save")) {
+        ImGui.text("Hello, World! " + FontAwesomeIcons.Smile);
+        if (ImGui.button(FontAwesomeIcons.Save + " Save")) {
             count++;
         }
         ImGui.sameLine();
@@ -53,6 +85,14 @@ public void process() {
         Extra.show(this);
     }
 
+    private static byte[] loadFromResources(String name) {
+        try {
+            return Files.readAllBytes(Paths.get(Main.class.getResource(name).toURI()));
+        } catch (IOException | URISyntaxException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     public static void main(final String[] args) {
         launch(new Main());
     }

example/src/main/java/Main.java

@@ -0,0 +1,98 @@
+package imgui;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Helper to build glyph ranges from text/string data. Feed your application strings/characters to it then call buildRanges().
+ * <p>
+ * You can use the ImFontGlyphRangesBuilder helper to create glyph ranges based on text input. For example: for a game where your script is known,
+ * if you can feed your entire script to it and only build the characters the game needs.
+ * <p>
+ * Direct reimplementation of native ImFontGlyphRangesBuilder in java
+ */
+public final class ImFontGlyphRangesBuilder {
+
+    private static final int UNICODE_CODEPOINT_MAX = 0xFFFF;
+
+    // have to use type long because values are unsigned integers
+    private final long[] usedChars = new long[(UNICODE_CODEPOINT_MAX + 1) / 8];
+
+    public ImFontGlyphRangesBuilder() {
+        clear();
+    }
+
+    /**
+     * Adds single character to resulting ranges
+     */
+    public void addChar(final char c) {
+        setBit(c);
+    }
+
+    /**
+     * Adds all characters from the given string to resulting ranges
+     */
+    public void addText(final String text) {
+        for (int i = 0; i < text.length(); i++) {
+            addChar(text.charAt(i));
+        }
+    }
+
+    /**
+     * Copies all given ranges to resulting ranges
+     */
+    public void addRanges(final short[] ranges) {
+        for (int i = 0; i < ranges.length; i += 2) {
+            if (ranges[i] == 0) {
+                break;
+            }
+
+            for (int k = ranges[i]; k <= ranges[i + 1]; k++) {
+                addChar((char) k);
+            }
+        }
+    }
+
+    /**
+     * Builds the final result (ordered ranges with all the unique characters submitted)
+     * Result of this function can be directly passed to ImFontAtlas
+     */
+    public short[] buildRanges() {
+        final List<Short> out = new ArrayList<>();
+        for (int n = 0; n <= UNICODE_CODEPOINT_MAX; n++) {
+            if (getBit(n)) {
+                out.add((short) n);
+                while (n < UNICODE_CODEPOINT_MAX && getBit(n + 1)) {
+                    n++;
+                }
+                out.add((short) n);
+            }
+        }
+
+        final short[] result = new short[out.size() + 1];
+        for (int i = 0; i < out.size(); i++) {
+            result[i] = out.get(i);
+        }
+        result[result.length - 1] = 0;
+        return result;
+    }
+
+    public void clear() {
+        Arrays.fill(usedChars, 0L);
+    }
+
+    public void setBit(final int n) {
+        final int off = n >> 5;
+        final long mask = 1L << (n & 31L);
+        usedChars[off] |= mask;
+    }
+
+    public boolean getBit(final int n) {
+        final int off = n >> 5;
+        final long mask = 1L << (n & 31L);
+        return (usedChars[off] & mask) > 0;
+    }
+
+
+}