(#470) Only use slice of size width*height*channels of image buffer (#491)

Author: s1hofmann

lib/provider/native/libnut-screen.class.spec.ts

@@ -35,7 +35,11 @@ describe("libnut screen action", () => {
         bytesPerPixel: 0,
         colorAt: jest.fn(),
         height: screenShotSize.height,
-        image: new ArrayBuffer(0),
+        image: Buffer.from(
+          new Array(screenShotSize.width * screenShotSize.height * 4 + 10).fill(
+            0
+          )
+        ),
         width: screenShotSize.width,
       }));
       libnut.getScreenSize = jest.fn(() => ({
@@ -51,6 +55,9 @@ describe("libnut screen action", () => {
       expect(image.height).toEqual(screenShotSize.height);
       expect(image.pixelDensity.scaleX).toEqual(2);
       expect(image.pixelDensity.scaleY).toEqual(2);
+      expect(image.data.length).toEqual(
+        screenShotSize.width * screenShotSize.height * 4
+      );
       expect(libnut.screen.capture).toBeCalledTimes(1);
     });
 
@@ -64,7 +71,11 @@ describe("libnut screen action", () => {
         bytesPerPixel: 0,
         colorAt: jest.fn(),
         height: screenShotSize.height,
-        image: new ArrayBuffer(0),
+        image: Buffer.from(
+          new Array(screenShotSize.width * screenShotSize.height * 4 + 10).fill(
+            0
+          )
+        ),
         width: screenShotSize.width,
       }));
 
@@ -76,6 +87,9 @@ describe("libnut screen action", () => {
       expect(image.height).toEqual(screenShotSize.height);
       expect(image.pixelDensity.scaleX).toEqual(20);
       expect(image.pixelDensity.scaleY).toEqual(20);
+      expect(image.data.length).toEqual(
+        screenShotSize.width * screenShotSize.height * 4
+      );
       expect(libnut.screen.capture).toBeCalledTimes(1);
     });
 

lib/provider/native/libnut-screen.class.ts

@@ -30,7 +30,7 @@ export default class ScreenAction implements ScreenProviderInterface {
           new Image(
             screenShot.width,
             screenShot.height,
-            screenShot.image,
+            screenShot.image.slice(0, screenShot.width * screenShot.height * 4),
             4,
             "grabScreenResult",
             screenShot.bitsPerPixel,
@@ -62,11 +62,11 @@ export default class ScreenAction implements ScreenProviderInterface {
           new Image(
             screenShot.width,
             screenShot.height,
-            screenShot.image,
+            screenShot.image.slice(0, screenShot.width * screenShot.height * 4),
             4,
             "grabScreenRegionResult",
-            4,
-            screenShot.width * 4,
+            screenShot.bitsPerPixel,
+            screenShot.byteWidth,
             ColorMode.BGR,
             pixelScaling
           )