add test for Bitmap readPixels and fix installPixels (#271)

Co-authored-by: Oleksandr Karpovich <oleksandr.karpovich@jetbrains.com>

skiko/src/commonMain/cpp/generated/Bitmap.cc

@@ -142,9 +142,12 @@ SKIKO_EXPORT KBoolean org_jetbrains_skia_Bitmap__1nAllocPixelsRowBytes
     return instance->tryAllocPixels(imageInfo, rowBytes);
 }
 
+void deletePixelsBytes(void* addr, void*) {
+    free(addr);
+}
 
 SKIKO_EXPORT KBoolean org_jetbrains_skia_Bitmap__1nInstallPixels
-  (KNativePointer ptr, KInt width, KInt height, KInt colorType, KInt alphaType, KNativePointer colorSpacePtr, KByte* pixelsArr, KInt rowBytes) {
+  (KNativePointer ptr, KInt width, KInt height, KInt colorType, KInt alphaType, KNativePointer colorSpacePtr, KByte* pixelsArr, KInt rowBytes, KInt pixelsLen) {
   SkBitmap* instance = reinterpret_cast<SkBitmap*>(ptr);
   SkColorSpace* colorSpace = reinterpret_cast<SkColorSpace*>(colorSpacePtr);
   SkImageInfo imageInfo = SkImageInfo::Make(width,
@@ -152,7 +155,11 @@ SKIKO_EXPORT KBoolean org_jetbrains_skia_Bitmap__1nInstallPixels
                                             static_cast<SkColorType>(colorType),
                                             static_cast<SkAlphaType>(alphaType),
                                             sk_ref_sp<SkColorSpace>(colorSpace));
-  return instance->installPixels(imageInfo, pixelsArr, rowBytes, nullptr, nullptr);
+
+  KNativePointer copyPtr = malloc(pixelsLen);
+  void* copy = memcpy(copyPtr, pixelsArr, pixelsLen);
+
+  return instance->installPixels(imageInfo, copy, rowBytes, deletePixelsBytes, nullptr);
 }
 
 SKIKO_EXPORT KBoolean org_jetbrains_skia_Bitmap__1nAllocPixels

skiko/src/commonMain/kotlin/org/jetbrains/skia/Bitmap.kt

@@ -571,7 +571,8 @@ class Bitmap internal constructor(ptr: NativePointer) : Managed(ptr, _FinalizerH
                     info.colorInfo.alphaType.ordinal,
                     getPtr(info.colorInfo.colorSpace),
                     toInterop(pixels),
-                    rowBytes
+                    rowBytes,
+                    pixels?.size ?: 0
                 )
             }
         } finally {
@@ -1128,7 +1129,8 @@ private external fun _nInstallPixels(
     alphaType: Int,
     colorSpacePtr: NativePointer,
     pixels: InteropPointer,
-    rowBytes: Int
+    rowBytes: Int,
+    pixelsLen: Int
 ): Boolean
 
 

skiko/src/commonTest/kotlin/org/jetbrains/skia/BitmapTest.kt

@@ -69,6 +69,23 @@ class BitmapTest {
         assertEquals(5 * bitmap.rowBytes, result.size)
     }
 
+    @Test //fixed bug https://github.com/JetBrains/skiko/pull/266
+    fun canReadPixelsWithGivenRowBytes() = runTest {
+        val bitmap = Bitmap()
+        bitmap.allocPixels(ImageInfo.makeS32(15, 15, ColorAlphaType.OPAQUE))
+
+        val newImageInfo = ImageInfo.makeS32(5, 5, ColorAlphaType.OPAQUE)
+
+        val result = bitmap.readPixels(
+            srcY = 1, srcX = 1,
+            dstInfo = newImageInfo,
+            dstRowBytes = newImageInfo.minRowBytes
+        )!!
+
+        assertTrue(newImageInfo.minRowBytes > 0 && newImageInfo.minRowBytes < bitmap.rowBytes)
+        assertEquals(newImageInfo.minRowBytes * 5, result.size)
+    }
+
     @Test
     fun canInstallPixels() = runTest {
         val bitmap = Bitmap()
@@ -79,7 +96,7 @@ class BitmapTest {
 
         val result = bitmap.readPixels()!!
         assertTrue(bitmap.rowBytes > 0)
-        assertEquals(16, result.size)
+        assertEquals(setArray.size, result.size)
         assertContentEquals(setArray, result)
     }
 }

skiko/src/jvmMain/cpp/common/Bitmap.cc

@@ -133,7 +133,7 @@ extern "C" JNIEXPORT jboolean JNICALL Java_org_jetbrains_skia_BitmapKt__1nAllocP
 }
 
 extern "C" JNIEXPORT jboolean JNICALL Java_org_jetbrains_skia_BitmapKt__1nInstallPixels
-  (JNIEnv* env, jclass jclass, jlong ptr, jint width, jint height, jint colorType, jint alphaType, jlong colorSpacePtr, jbyteArray pixelsArr, jint rowBytes) {
+  (JNIEnv* env, jclass jclass, jlong ptr, jint width, jint height, jint colorType, jint alphaType, jlong colorSpacePtr, jbyteArray pixelsArr, jint rowBytes, jint pixelsLen) {
     SkBitmap* instance = reinterpret_cast<SkBitmap*>(static_cast<uintptr_t>(ptr));
     SkColorSpace* colorSpace = reinterpret_cast<SkColorSpace*>(static_cast<uintptr_t>(colorSpacePtr));
     SkImageInfo imageInfo = SkImageInfo::Make(width,
@@ -142,9 +142,8 @@ extern "C" JNIEXPORT jboolean JNICALL Java_org_jetbrains_skia_BitmapKt__1nInstal
                                               static_cast<SkAlphaType>(alphaType),
                                               sk_ref_sp<SkColorSpace>(colorSpace));
 
-    jsize len = env->GetArrayLength(pixelsArr);
-    jbyte* pixels = new jbyte[len];
-    env->GetByteArrayRegion(pixelsArr, 0, len, pixels);
+    jbyte* pixels = new jbyte[pixelsLen];
+    env->GetByteArrayRegion(pixelsArr, 0, pixelsLen, pixels);
     return instance->installPixels(imageInfo, pixels, rowBytes, deleteJBytes, nullptr);
 }