Enabling Nativescript-screenshot for {N} 7/8

[dlcole]

Hi! 👋

Firstly, thanks for your work on this project! 🙂

Today I used patch-package to patch nativescript-screenshot@0.0.2 for the project I'm working on.

I revised the package to be compatible with the breaking changes in NativeScript 7 and 8: changing the import statement, replacing "exports." with "export", and modifying the ImageSource instantiation on iOS. It turns out ImageSource.fromData now returns a promise, so I modified the Android code to likewise return a promise. This means anyone invoking screenshot.getImage must now expect a promise, but their code would be broken on iOS anyway if they didn't.

Here is the diff that solved my problem:

diff --git a/node_modules/nativescript-screenshot/index.js b/node_modules/nativescript-screenshot/index.js
index 8be9bef..6c67b19 100644
--- a/node_modules/nativescript-screenshot/index.js
+++ b/node_modules/nativescript-screenshot/index.js
@@ -1,20 +1,20 @@
-var imageSource = require("image-source");
+import { ImageSource } from '@nativescript/core';
 
-exports.getImage = function(view) {
+export function getImage(view) {
     if (view.ios) {
         UIGraphicsBeginImageContextWithOptions(view.ios.frame.size, false, 0);
         view.ios.drawViewHierarchyInRectAfterScreenUpdates(CGRectMake(0, 0, view.ios.frame.size.width, view.ios.frame.size.height), true);
         var imageFromCurrentImageContext = UIGraphicsGetImageFromCurrentImageContext();
         UIGraphicsEndImageContext();
-        return imageSource.fromData(UIImagePNGRepresentation(imageFromCurrentImageContext));
+        return ImageSource.fromData(UIImagePNGRepresentation(imageFromCurrentImageContext)); // returns Promise
         
     } else if (view.android) {
         view.android.setDrawingCacheEnabled(true);
         var bmp = android.graphics.Bitmap.createBitmap(view.android.getDrawingCache());
         view.android.setDrawingCacheEnabled(false);
-        var source = new imageSource.ImageSource();
+        var source = new ImageSource;
         source.setNativeSource(bmp);
-        return source;
+        return Promise.resolve(source);
     }
     return undefined;
 }
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