Add API to access fonts from resources. (#509)

* Add API to access fonts from resources.

* More font locations

skiko/build.gradle.kts

@@ -4,7 +4,6 @@ import org.gradle.api.tasks.testing.AbstractTestTask
 import org.jetbrains.compose.internal.publishing.MavenCentralProperties
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
 import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 
 plugins {

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

@@ -5,6 +5,7 @@ import java.awt.Font
 import java.awt.FontFormatException
 import java.io.File
 import java.io.FileInputStream
+import java.io.FileOutputStream
 import java.io.IOException
 import java.util.concurrent.ConcurrentHashMap
 
@@ -42,6 +43,8 @@ class AwtFontManager(fontPaths: Array<String> = emptyArray()) {
             OS.Linux -> {
                 val pathsToCheck = arrayOf(
                     System.getProperty("user.home") + File.separator + ".fonts",
+                    "/usr/share/fonts",
+                    "/usr/local/share/fonts",
                     "/usr/share/fonts/truetype",
                     "/usr/share/fonts/TTF"
                 )
@@ -61,12 +64,18 @@ class AwtFontManager(fontPaths: Array<String> = emptyArray()) {
         }
     }
 
+    private fun isFont(extension: String): Boolean {
+        return extension == "ttf" ||
+               extension == "ttc" ||
+               extension == "otf"
+    }
+
     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 {
+                fontDirectory.walk().filter { it.isFile && isFont(it.extension.lowercase()) }.forEach {
                     files.add(it)
                 }
             }
@@ -74,20 +83,31 @@ class AwtFontManager(fontPaths: Array<String> = emptyArray()) {
         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 {
+    private fun addFontFromFile(file: File): Boolean {
+        val f = try {
+            FileInputStream(file.absolutePath).use {
                 Font.createFont(Font.TRUETYPE_FONT, it)
             }
+        } catch (e: FontFormatException){
+            return false
+        } catch (e: IOException) {
+            return false
+        }
         val name = f.family
 
         val list = fontsMap.computeIfAbsent(name) { mutableListOf() }
         synchronized(list) {
             list.add(FontDescriptor(file.absoluteFile, f.style))
         }
+        return true
+    }
+
+    private suspend fun cacheAllFonts() {
+        fontsMap.clear()
+        val fontFiles = findFontFiles(customFontPaths) + findFontFiles(systemFontsPaths())
+        for (file in fontFiles) {
+            try {
+                addFontFromFile(file)
                 yield()
             } catch (e: FontFormatException) {
             } catch (e: IOException) {
@@ -186,6 +206,26 @@ class AwtFontManager(fontPaths: Array<String> = emptyArray()) {
         customFontPaths += path
     }
 
+    /**
+     * Add custom resource entry as a font known to this resource manager.
+     *
+     * @return true, if font was found and identified, and false otherwise
+     */
+    fun addResourceFont(resource: String, loader: ClassLoader = Thread.currentThread().contextClassLoader): Boolean {
+        val res = loader.getResourceAsStream(resource) ?: ClassLoader.getSystemResourceAsStream(resource) ?: return false
+        val file = File.createTempFile("tmp", ".ttf")
+        file.deleteOnExit()
+        FileOutputStream(file).use { out ->
+            out.write(res.readAllBytes())
+        }
+        return addFontFromFile(file).also {
+            if (it)
+                customFontPaths += file.absolutePath
+            else
+                file.delete()
+        }
+    }
+
     /**
      * If all AWT fonts were cached. Check this property before using non-suspend version
      * of font conversion APIs.

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

@@ -93,4 +93,19 @@ class AwtFontInterop {
             assertTrue("Font must be file", path.exists() && path.isFile)
         }
     }
+
+    // This test is disabled due to convoluted setup of tests.
+    // @Test
+    fun addCustomResource() {
+        runTest {
+            assumeOk()
+            val fontManager = AwtFontManager()
+            assertTrue("Custom resource must be found",
+                fontManager.addResourceFont("/fonts/JetBrainsMono-Bold.ttf", Library.javaClass.classLoader))
+            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