Scrimage should output helper when image loading fails (#269)

* Fix PNG image compression PNG image compression

* Added .exe to windows paths

* Scrimage should output helper when image loading fails #251

scrimage-core/src/main/java/com/sksamuel/scrimage/ImageParseException.java

@@ -1,5 +1,7 @@
 package com.sksamuel.scrimage;
 
+import com.sksamuel.scrimage.format.Format;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
@@ -14,7 +16,12 @@ public ImageParseException() {
    }
 
    public ImageParseException(List<Throwable> errors) {
-      super("Image parsing failed. Tried the following ImageReader implementations:\n" + errors.stream().map(Throwable::getMessage).collect(Collectors.joining("\n")));
+      super("Image parsing failed for unknown image format. Tried the following ImageReader implementations:\n" + errors.stream().map(Throwable::getMessage).collect(Collectors.joining("\n")));
+      this.errors = errors;
+   }
+
+   public ImageParseException(List<Throwable> errors, Format format) {
+      super("Image parsing failed for " + format + ". If the format is `webp` ensure you have a webp reader on your classpath, such as the `scrimage-webp` module. Tried the following ImageReader implementations:\n" + errors.stream().map(Throwable::getMessage).collect(Collectors.joining("\n")));
       this.errors = errors;
    }
 

scrimage-core/src/main/java/com/sksamuel/scrimage/nio/ImageIOReader.java

@@ -74,4 +74,9 @@ public ImmutableImage read(byte[] bytes, Rectangle rectangle) throws IOException
       else
          throw new IOException("No javax.imageio.ImageReader supported this image format; tried " + attempts.size() + " readers; errors=" + attempts);
    }
+
+   @Override
+   public String toString() {
+      return "com.sksamuel.scrimage.nio.ImageIOReader (delegates to the JDK javax.imageio readers)";
+   }
 }

scrimage-core/src/main/java/com/sksamuel/scrimage/nio/ImageReaders.java

@@ -2,11 +2,14 @@
 
 import com.sksamuel.scrimage.ImageParseException;
 import com.sksamuel.scrimage.ImmutableImage;
+import com.sksamuel.scrimage.format.Format;
+import com.sksamuel.scrimage.format.FormatDetector;
 
 import java.awt.*;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 import java.util.ServiceLoader;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
@@ -37,15 +40,16 @@ public static ImmutableImage read(ImageSource source, Rectangle rectangle, Class
    /**
     * Attempts to read an image from the given source, using the supplied image readers.
     *
-    * @param source the image source
+    * @param source    the image source
     * @param rectangle an optional subset of the image to read.
-    * @param readers the readers that should be used to attempt to load this image.
+    * @param readers   the readers that should be used to attempt to load this image.
     */
    public static ImmutableImage read(ImageSource source, Rectangle rectangle, List<ImageReader> readers) throws IOException {
       List<Throwable> errors = new ArrayList<>();
+      byte[] bytes = source.read();
       for (ImageReader reader : readers) {
          try {
-            ImmutableImage image = reader.read(source.read(), rectangle);
+            ImmutableImage image = reader.read(bytes, rectangle);
             if (image == null) {
                errors.add(new IOException(reader + " failed"));
             } else {
@@ -55,9 +59,10 @@ public static ImmutableImage read(ImageSource source, Rectangle rectangle, List<
             errors.add(new IOException(reader.toString() + " failed due to " + e.getMessage(), e));
          }
       }
-      if (errors.isEmpty())
-         throw new ImageParseException();
-      else
+      Format format = FormatDetector.detect(bytes).orElse(null);
+      if (format == null)
          throw new ImageParseException(errors);
+      else
+         throw new ImageParseException(errors, format);
    }
 }

scrimage-core/src/main/java/com/sksamuel/scrimage/nio/OpenGifReader.java

@@ -32,4 +32,9 @@ public List<ImmutableImage> readAll(byte[] bytes) throws IOException {
       }
       return images;
    }
+
+   @Override
+   public String toString() {
+      return "com.sksamuel.scrimage.nio.OpenGifReader (delegates to at.dhyan.open_imaging)";
+   }
 }

scrimage-core/src/main/java/com/sksamuel/scrimage/nio/PngReader.java

@@ -94,4 +94,9 @@ private boolean isPng(byte[] bytes) {
       System.arraycopy(bytes, 0, actual, 0, 8);
       return Arrays.equals(expected, actual);
    }
+
+   @Override
+   public String toString() {
+      return "com.sksamuel.scrimage.nio.PngReader (delegates to ar.com.hjg.pngj)";
+   }
 }

scrimage-tests/build.gradle.kts

@@ -12,9 +12,9 @@ dependencies {
    implementation(project(":scrimage-core"))
    testImplementation(kotlin("stdlib"))
    testImplementation(kotlin("stdlib-jdk8"))
-   testImplementation("io.kotest:kotest-framework-datatest:5.5.4")
-   testImplementation("io.kotest:kotest-runner-junit5:5.5.4")
-   testImplementation("io.kotest:kotest-assertions-core:5.5.4")
+   testImplementation("io.kotest:kotest-framework-datatest:5.5.5")
+   testImplementation("io.kotest:kotest-runner-junit5:5.5.5")
+   testImplementation("io.kotest:kotest-assertions-core:5.5.5")
 }
 
 java {

scrimage-tests/src/test/kotlin/com/sksamuel/scrimage/core/FormatDetectorTest.kt

@@ -2,8 +2,11 @@ package com.sksamuel.scrimage.core
 
 import com.sksamuel.scrimage.format.Format
 import com.sksamuel.scrimage.format.FormatDetector
+import com.sksamuel.scrimage.nio.ImmutableImageLoader
+import io.kotest.assertions.throwables.shouldThrowAny
 import io.kotest.core.spec.style.WordSpec
 import io.kotest.matchers.shouldBe
+import io.kotest.matchers.string.shouldContain
 
 class FormatDetectorTest : WordSpec({
 
@@ -22,4 +25,12 @@ class FormatDetectorTest : WordSpec({
       }
    }
 
+   "image loader" should {
+      "output webp warning" {
+         shouldThrowAny {
+            ImmutableImageLoader.create().fromResource("/spacedock.webp")
+         }.message shouldContain "Image parsing failed for WEBP"
+      }
+   }
+
 })

scrimage-tests/src/test/kotlin/com/sksamuel/scrimage/core/nio/MultipleImageLoaderExceptionErrorTest.kt

@@ -13,7 +13,7 @@ class MultipleImageLoaderExceptionErrorTest : FunSpec() {
          val e = shouldThrowAny {
             ImmutableImageLoader.create().load(ImageSource.of(bytes))
          }
-         e.message shouldContain """Image parsing failed. Tried the following ImageReader implementations"""
+         e.message shouldContain """Image parsing failed for unknown image format. Tried the following ImageReader implementations"""
          e.message shouldContain """com.sksamuel.scrimage.nio.ImageIOReader"""
          e.message shouldContain """com.sksamuel.scrimage.nio.PngReader"""
          e.message shouldContain """com.sksamuel.scrimage.nio.OpenGifReader"""

scrimage-webp/src/main/java/com/sksamuel/scrimage/webp/WebpHandler.java

@@ -48,10 +48,14 @@ protected static String[] getBinaryPaths(String binaryName) {
       if (SystemUtils.IS_OS_WINDOWS) {
          return new String[]{
             "/webp_binaries/" + binaryName,
+            "/webp_binaries/" + binaryName + ".exe",
             // typo from previous versions must be left in
             "/webp_binaries/window/" + binaryName,
+            "/webp_binaries/window/" + binaryName + ".exe",
             "/webp_binaries/windows/" + binaryName,
+            "/webp_binaries/windows/" + binaryName + ".exe",
             "/dist_webp_binaries/libwebp-1.3.0-windows-x64/bin/" + binaryName,
+            "/dist_webp_binaries/libwebp-1.3.0-windows-x64/bin/" + binaryName + ".exe",
          };
       } else if (SystemUtils.IS_OS_MAC) {
          return new String[]{