Improve ImageAsset scaling (#5110)

* Do not depend on current device screen while calculating Image Asset size.

* Scale the image asset to the exact requested size.

* Process image assets natively, pass keepAspectRatio based on the stretch property and Asset options.

* Fixed the splashscreen resource name as it cannot be read when containing a dot.

* Updated the Image Asset scale and rotate logic based on the Native one.

* Make the ImageAsset size more important than the Image decode size as its more specific.

* Fixed tslint errors.

* Added filePath support in the ImageAsset constructor for iOS in order to unify it with the Android implementation, support for relative files and file not found support errors.

* Added unit tests for ImageAssets.

* Added a sample app for UI testing of image-view with ImageAsset src.

* chore: apply PR comments

tests/app/image-source/image-source-tests.ts

@@ -1,10 +1,14 @@
 import * as imageSource from "tns-core-modules/image-source";
+import * as imageAssetModule from "tns-core-modules/image-asset";
 import * as fs from "tns-core-modules/file-system";
 import * as app from "tns-core-modules/application";
 import * as TKUnit from "../TKUnit";
 import * as platform from "tns-core-modules/platform";
 
 const imagePath = "~/logo.png";
+const splashscreenPath = "~/splashscreen.png";
+const splashscreenWidth = 372;
+const splashscreenHeight = 218;
 const smallImagePath = "~/small-image.png";
 
 export function testFromResource() {
@@ -65,6 +69,96 @@ export function testFromFile() {
     TKUnit.assert(!fs.File.exists(path), "test.png not removed");
 }
 
+export function testFromAssetFileNotFound(done) {
+    let asset = new imageAssetModule.ImageAsset('invalidFile.png');
+    asset.options = {
+        width: 0,
+        height: 0,
+        keepAspectRatio: true
+    };
+
+    let img = imageSource.fromAsset(asset).then((source) => {
+        done('Should not resolve with invalid file name.');
+    }, (error) => {
+        TKUnit.assertNotNull(error);
+        done();
+    });
+}
+
+export function testFromAssetSimple(done) {
+    let asset = new imageAssetModule.ImageAsset(splashscreenPath);
+    asset.options = {
+        width: 0,
+        height: 0,
+        keepAspectRatio: true
+    };
+
+    let img = imageSource.fromAsset(asset).then((source) => {
+        TKUnit.assertEqual(source.width, splashscreenWidth);
+        TKUnit.assertEqual(source.height, splashscreenHeight);
+        done();
+    }, (error) => {
+        done(error);
+    });
+}
+
+export function testFromAssetWithScaling(done) {
+    let asset = new imageAssetModule.ImageAsset(splashscreenPath);
+    let scaleWidth = 10;
+    let scaleHeight = 11;
+    asset.options = {
+        width: scaleWidth,
+        height: scaleHeight,
+        keepAspectRatio: false
+    };
+
+    let img = imageSource.fromAsset(asset).then((source) => {
+        TKUnit.assertEqual(source.width, scaleWidth);
+        TKUnit.assertEqual(source.height, scaleHeight);
+        done();
+    }, (error) => {
+        done(error);
+    });
+}
+
+export function testFromAssetWithScalingAndAspectRatio(done) {
+    let asset = new imageAssetModule.ImageAsset(splashscreenPath);
+    let scaleWidth = 10;
+    let scaleHeight = 11;
+    asset.options = {
+        width: scaleWidth,
+        height: scaleHeight,
+        keepAspectRatio: true
+    };
+
+    let img = imageSource.fromAsset(asset).then((source) => {
+        TKUnit.assertEqual(source.width, scaleWidth);
+        TKUnit.assertEqual(source.height, 5);
+        done();
+    }, (error) => {
+        done(error);
+    });
+}
+
+export function testFromAssetWithBiggerScaling(done) {
+    let asset = new imageAssetModule.ImageAsset(splashscreenPath);
+    let scaleWidth = 600;
+    let scaleHeight = 600;
+    asset.options = {
+        width: scaleWidth,
+        height: scaleHeight,
+        keepAspectRatio: false
+    };
+
+    let img = imageSource.fromAsset(asset).then((source) => {
+        TKUnit.assertEqual(source.width, scaleWidth);
+        TKUnit.assertEqual(source.height, scaleHeight);
+        done();
+    }, (error) => {
+        done(error);
+    });
+}
+
 export function testNativeFields() {
     const img = imageSource.fromFile(imagePath);
     if (app.android) {

tests/app/ui/image/image-tests.ts

@@ -138,7 +138,8 @@ export const test_SettingImageSrcToDataURI_async = function (done) {
 
 export function test_imageSourceNotResetAfterCreateUI() {
     let image = new ImageModule.Image();
-    let imageSource = ImageSourceModule.fromResource("splashscreen.9");
+    let imageSource = ImageSourceModule.fromResource("splashscreen");
+    TKUnit.assertNotEqual(null, imageSource);
     image.imageSource = imageSource;
     helper.buildUIAndRunTest(image, () => {
         TKUnit.waitUntilReady(() => image.isLoaded);