AWT fonts interop support (#448)

skiko/build.gradle.kts

@@ -308,6 +308,9 @@ kotlin {
 
         val awtTest by getting {
             dependsOn(jvmTest)
+            dependencies {
+                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-swing:$coroutinesVersion")
+            }
         }
 
         if (supportAndroid) {
@@ -1031,6 +1034,8 @@ tasks.withType<Test>().configureEach {
         systemProperty("skiko.jar.path", jar.absolutePath)
 
         systemProperty("skiko.test.screenshots.dir", File(project.projectDir, "src/jvmTest/screenshots").absolutePath)
+        systemProperty("skiko.test.font.dir", File(project.projectDir, "src/commonTest/resources/fonts").absolutePath)
+
         systemProperty("skiko.test.ui.enabled", System.getProperty("skiko.test.ui.enabled", "false"))
         systemProperty("skiko.test.ui.renderApi", System.getProperty("skiko.test.ui.renderApi", "all"))
 

skiko/src/awtMain/kotlin/org/jetbrains/skiko/Convertors.jvm.kt

 package org.jetbrains.skiko
 
-import org.jetbrains.skia.Bitmap
-import org.jetbrains.skia.ColorAlphaType
-import org.jetbrains.skia.ColorType
-import org.jetbrains.skia.ImageInfo
-import org.jetbrains.skia.Image
+import org.jetbrains.skia.*
 import org.jetbrains.skia.impl.BufferUtil
 import java.awt.Transparency
 import java.awt.color.ColorSpace
@@ -210,3 +206,9 @@ private fun toSkikoKey(event: KeyEvent): Int {
     }
     return key
 }
+
+suspend fun java.awt.Font.toSkikoTypeface(): Typeface? {
+    val file = AwtFontManager.DEFAULT.findFontFile(this) ?: return null
+    val data = file.readBytes()
+    return Typeface.makeFromData(Data.makeFromBytes(data))
+}
\ No newline at end of file

skiko/src/awtMain/kotlin/org/jetbrains/skiko/FontInterop.awt.kt

+package org.jetbrains.skiko
+
+import kotlinx.coroutines.*
+import java.awt.Font
+import java.awt.FontFormatException
+import java.io.File
+import java.io.FileInputStream
+import java.io.IOException
+import java.util.concurrent.ConcurrentHashMap
+
+class AwtFontManager(fontPaths: Array<String> = emptyArray()) {
+    private var fontsMap = ConcurrentHashMap<String, File>()
+    @Volatile
+    private var allFontsCachedImpl = false
+    private val waitChannel = RendezvousBroadcastChannel<Int>()
+    private var customFontPaths = mutableListOf(*fontPaths)
+    private var cacheJob: Job? = null
+
+    init {
+        invalidate()
+    }
+
+    private fun systemFontsPaths(): List<String> {
+        return when (hostOs) {
+            OS.Windows -> {
+                val winPath = System.getenv("WINDIR")
+                val localAppPath = System.getenv("LOCALAPPDATA")
+                listOf(
+                    "$winPath\\Fonts",
+                    "$localAppPath\\Microsoft\\Windows\\Fonts"
+                )
+            }
+            OS.MacOS -> {
+                listOf(
+                    System.getProperty("user.home") + File.separator + "Library/Fonts",
+                    "/Library/Fonts",
+                    "/System/Library/Fonts"
+                )
+            }
+            OS.Linux -> {
+                val pathsToCheck = arrayOf(
+                    System.getProperty("user.home") + File.separator + ".fonts",
+                    "/usr/share/fonts/truetype",
+                    "/usr/share/fonts/TTF"
+                )
+                val resultList = ArrayList<String>()
+                for (i in pathsToCheck.indices.reversed()) {
+                    val path = pathsToCheck[i]
+                    val tmp = File(path)
+                    if (tmp.exists() && tmp.isDirectory && tmp.canRead()) {
+                        resultList.add(path)
+                    }
+                }
+                resultList
+            }
+            else -> {
+                throw RuntimeException("Unknown OS: $hostOs")
+            }
+        }
+    }
+
+    private fun findFontFiles(paths: List<String>): List<File> {
+        val files = mutableListOf<File>()
+        paths.forEach { path ->
+            val fontDirectory = File(path)
+            if (fontDirectory.exists()) {
+                fontDirectory.walk().filter { it.isFile && it.extension.lowercase() == "ttf" }.forEach {
+                    files.add(it)
+                }
+            }
+        }
+        return files
+    }
+
+    private suspend fun cacheAllFonts() {
+        fontsMap.clear()
+        val fontFiles = findFontFiles(customFontPaths) + findFontFiles(systemFontsPaths())
+        for (file in fontFiles) {
+            try {
+                val f = FileInputStream(file.absolutePath).use {
+                    Font.createFont(Font.TRUETYPE_FONT, it)
+                }
+                val name = f.family
+                fontsMap[name] = file.absoluteFile
+                yield()
+            } catch (e: FontFormatException) {
+            } catch (e: IOException) {
+            }
+        }
+    }
+
+    /**
+     * Find font file path from an AWT font.
+     * As font finding is long IO-intensive process, this operation checks if given font
+     * is already known to the font manager.
+     *
+     * If you want stable and predictable result it's better use [findFontFile] or check [allFontsCached].
+     *
+     * @param font - AWT font for which we need to know the path
+     * @return path to font, if known
+     */
+    @DelicateSkikoApi
+    fun findAvailableFontFile(font: Font): File? {
+        return fontsMap[font.family]
+    }
+
+    /**
+     * Show all fonts currently known to AWT font manager. As font indexing could take time,
+     * may have not all elements.
+     *
+     * If you want stable and predictable result it's better use [listFontFiles] or check [allFontsCached].
+     *
+     * @return list of currently known fonts
+     */
+    @DelicateSkikoApi
+    fun listAvailableFontFiles(): List<File> {
+        return fontsMap.values.toList()
+    }
+
+    /**
+     * Show all fonts known to AWT font manager.
+     * @return list of known fonts
+     */
+    suspend fun listFontFiles(): List<File> {
+        waitAllFontsCached()
+        return fontsMap.values.toList()
+    }
+
+    /**
+     * Find font file path from an AWT font.
+     * As font finding is long IO-intensive process, this operation may suspend for pretty long time.
+     * @param font - which AWT font to look for
+     * @return path to the font file or null, if not found
+     */
+    suspend fun findFontFile(font: Font): File? {
+        waitAllFontsCached()
+        return fontsMap[font.family]
+    }
+
+    /**
+     * Find font file path from the family name.
+     * As font finding is long IO-intensive process, this operation may suspend for pretty long time.
+     * @param family - which AWT font to look for
+     * @return path to the font file or null, if not found
+     */
+    suspend fun findFontFamilyFile(family: String): File? {
+        waitAllFontsCached()
+        return fontsMap[family]
+    }
+
+    /**
+     * Invalidate cache and start caching again. Maybe useful to re-read fonts
+     * when changed.
+     */
+    fun invalidate() {
+        cacheJob?.let {
+            it.cancel()
+        }
+        allFontsCachedImpl = false
+        cacheJob = GlobalScope.launch(Dispatchers.IO) {
+            cacheAllFonts()
+            allFontsCachedImpl = true
+            waitChannel.sendAll(1)
+        }
+    }
+
+    /**
+     * Add custom directory to font search paths. Call [invalidate]
+     * for operation to take effect.
+     */
+    fun addCustomPath(path: String) {
+        customFontPaths += path
+    }
+
+    /**
+     * If all AWT fonts were cached. Check this property before using non-suspend version
+     * of font conversion APIs.
+     */
+    @DelicateSkikoApi
+    val allFontsCached: Boolean
+        get() = allFontsCachedImpl
+
+    /**
+     * Call continuation only when all AWT fonts are cached.
+     * Please avoid this API and prefer suspend operations.
+     */
+    @DelicateSkikoApi
+    fun whenAllFontsCachedBlocking(continuation: () -> Unit) {
+        // TODO: avoid busy loop
+        while (!allFontsCachedImpl) {}
+        continuation()
+    }
+
+    /**
+     * Suspend until all AWT fonts were cached.
+     */
+    private suspend fun waitAllFontsCached() {
+        if (!allFontsCachedImpl) {
+            waitChannel.receive()
+        }
+    }
+
+    companion object {
+        val DEFAULT by lazy { AwtFontManager() }
+    }
+}

skiko/src/awtTest/kotlin/org/jetbrains/skiko/AwtFontInterop.kt

+package org.jetbrains.skiko
+
+import org.jetbrains.skiko.tests.runTest
+import org.junit.Assert.assertTrue
+import org.junit.Assume
+import org.junit.Test
+import java.awt.Font
+import java.awt.GraphicsEnvironment
+
+class AwtFontInterop {
+    private val fontManager = AwtFontManager()
+
+    private fun assumeOk() {
+        Assume.assumeFalse(GraphicsEnvironment.isHeadless())
+        Assume.assumeTrue(hostOs != OS.Linux)
+    }
+
+    @OptIn(DelicateSkikoApi::class)
+    @Test
+    fun canFindAvailableFont() = fontManager.whenAllFontsCachedBlocking {
+        assumeOk()
+        val font = Font("Verdana", Font.BOLD, 12)
+        val path = fontManager.findAvailableFontFile(font)
+        assertTrue("Font must be found", path != null)
+        path!!
+        assertTrue("Font must be file", path.exists() && path.isFile)
+    }
+
+    @Test
+    fun canFindFont() {
+        runTest {
+            assumeOk()
+            val font = Font("Verdana", Font.BOLD, 12)
+            val path = fontManager.findFontFile(font)
+            assertTrue("Font must be found", path != null)
+            path!!
+            assertTrue("Font must be file", path.exists() && path.isFile)
+        }
+    }
+
+    @Test
+    fun canFindFamily() {
+        runTest {
+            assumeOk()
+            val path = fontManager.findFontFamilyFile("Verdana")
+            assertTrue("Font must be found", path != null)
+            path!!
+            assertTrue("Font must be file", path.exists() && path.isFile)
+        }
+    }
+
+    @OptIn(DelicateSkikoApi::class)
+    @Test
+    fun nonExistentFont() = fontManager.whenAllFontsCachedBlocking {
+        assumeOk()
+        val font = Font("XXXYYY745", Font.BOLD, 12)
+        val path = fontManager.findAvailableFontFile(font)
+        assertTrue("Font must not be found", path == null)
+    }
+
+    @Test
+    fun makeSkikoTypeface() {
+        runTest {
+            assumeOk()
+            Assume.assumeFalse(GraphicsEnvironment.isHeadless())
+            val font = Font("Verdana", Font.BOLD, 12)
+            val skikoTypeface = font.toSkikoTypeface()
+            assertTrue("Skiko typeface must work", skikoTypeface != null)
+            skikoTypeface!!
+            assertTrue("Skiko typeface name is incorrect: ${skikoTypeface.familyName}", skikoTypeface.familyName == "Verdana")
+        }
+    }
+
+    @Test
+    fun listAllFonts() {
+        runTest {
+            assumeOk()
+            val fontFiles = fontManager.listFontFiles()
+            assertTrue("There must be fonts", fontFiles.isNotEmpty())
+        }
+    }
+
+    @Test
+    fun addCustomPath() {
+        runTest {
+            assumeOk()
+            val resDir = System.getProperty("skiko.test.font.dir")!!
+            fontManager.addCustomPath(resDir)
+            fontManager.invalidate()
+            val path = fontManager.findFontFamilyFile("JetBrains Mono")
+            assertTrue("Custom font must be found", path != null)
+            path!!
+            assertTrue("Font must be file", path.exists() && path.isFile)
+        }
+    }
+}
\ No newline at end of file

skiko/src/commonMain/kotlin/org/jetbrains/skiko/Annotations.kt

+package org.jetbrains.skiko
+
+/**
+ * Marks declarations that are **delicate** —
+ * they have limited use-case and shall be used with care in general code.
+ * Any use of a delicate declaration has to be carefully reviewed to make sure it is
+ * properly used and does not create problems like concurrency issues, memory and resource leaks.
+ * Carefully read documentation of any declaration marked as `DelicateSkikoApi`.
+ */
+@MustBeDocumented
+@Retention(value = AnnotationRetention.BINARY)
+@RequiresOptIn(
+    level = RequiresOptIn.Level.WARNING,
+    message = "This is a delicate API and its use requires care." +
+            " Make sure you fully read and understand documentation of the declaration that is marked as a delicate API."
+)
+annotation class DelicateSkikoApi
\ No newline at end of file