Css gradients (#5534)

* feat(ios): Added support for css gradients.

* feat(android): Added support for css gradients.

* fix: Fixed gradient borders on ios

* fix(gradient): added backgroundGradient to View and Style.

* fix(ios-gradients): fixed ios gradients covering view content.

* test(gradient): Added ui app tests for background gradients.

* test(gradient): Added a test ensuring background gradient property is applied to style.

* style(gradient): Fixed tslint errors.

* fix(gradient): Removed the background-gradient property and added the gradient to background-image.

* style: fixed a consecutive blank line tslint error.

* fix(tests): fixed the bug that was causing tests to fail.

* chore(linear-gradient): fix equality comparer

* test(gradient): add linear gradients test app

* chore(tslint): update with latest tslint rules

apps/app/ui-tests-app/button/border-playground.ts

@@ -34,6 +34,11 @@ export function onToggle(args: EventData) {
         target.backgroundImage = target.backgroundImage ? undefined : `~/ui-tests-app/resources/images/test2.png`; 
         debugConsole.text += `> background-image: ${target.backgroundImage}\n`;
     }
+    else if (button.text === "BGGradient") {
+        const gradient = "linear-gradient(to right, purple, red)";
+        target.backgroundImage = typeof target.backgroundImage === "object" ? undefined :  gradient;
+        debugConsole.text += `> background-image: ${gradient} \n`;
+    }
 
     scrollView.scrollToVerticalOffset(scrollView.scrollableHeight, true);
 }

apps/app/ui-tests-app/button/border-playground.xml

@@ -17,6 +17,7 @@
         <StackLayout id="target" row="1" col="1">
             <Button text="BGColor" tap="onToggle"/>
             <Button text="BGImage" tap="onToggle"/>
+            <Button text="BGGradient" tap="onToggle"/>
         </StackLayout>
         <StackLayout id="right" class="button-container" row="1" col="2">
             <Button text="Color" id="borderRightColor" tap="onToggle"/>

apps/app/ui-tests-app/css/background-image-linear-gradient.ts

@@ -0,0 +1,41 @@
+import * as pages from "tns-core-modules/ui/page";
+import { EventData } from "tns-core-modules/data/observable";
+import * as button from "tns-core-modules/ui/button";
+
+import { GridLayout } from "tns-core-modules/ui/layouts/grid-layout";
+
+let testIndex = 0;
+const tests = [
+    { name: "black-blue only", backgroundImage: "linear-gradient(to bottom, black, blue)"},
+    { name: "to bottom green-blue", backgroundImage: "linear-gradient(to bottom, green, blue)"},
+    { name: "to left yellow-blue", backgroundImage: "linear-gradient(to left, yellow, green)"},
+    { name: "to right yellow-blue", backgroundImage: "linear-gradient(to right, yellow, green)"},
+    { name: "-45deg green-blue", backgroundImage: "linear-gradient(-45deg, green, blue)"},
+    { name: "45deg green-blue", backgroundImage: "linear-gradient(45deg, green, blue)"},
+
+    { name: "black-blue-pink only", backgroundImage: "linear-gradient(to bottom, black, blue, pink)"},
+    { name: "to bottom green-blue-pink", backgroundImage: "linear-gradient(to bottom, green, blue, pink)"},
+    { name: "to left yellow-blue-pink", backgroundImage: "linear-gradient(to left, yellow, green, pink)"},
+    { name: "to right yellow-blue-pink", backgroundImage: "linear-gradient(to right, yellow, green, pink)"},
+    { name: "-45deg green-blue-pink", backgroundImage: "linear-gradient(-45deg, green, blue, pink)"},
+    { name: "45deg green-blue-pink", backgroundImage: "linear-gradient(45deg, green, blue, pink)"},
+]
+
+export function onLoaded(args) {
+    applyNextStyle(args);
+}
+
+export function onButtonTap(args) {
+    applyNextStyle(args);
+}
+
+function applyNextStyle(args) {
+    let page = <pages.Page>args.object.page;
+    let btn = <button.Button>args.object;
+    let gridElement = <GridLayout>page.getViewById("Container");
+
+    btn.text = tests[testIndex].name;
+    gridElement.backgroundImage = tests[testIndex].backgroundImage;
+
+    testIndex = testIndex < tests.length - 1 ? ++testIndex : 0;
+}

apps/app/ui-tests-app/css/background-image-linear-gradient.xml

@@ -0,0 +1,7 @@
+<Page xmlns="http://schemas.nativescript.org/tns.xsd" loaded="onLoaded">
+  <GridLayout rows="*, 7*">
+     <Button row="0" text="a1" tap="onButtonTap"/>
+
+    <GridLayout id="Container" fontSize="12" borderColor="black" margin="5" borderWidth="1" row="1"/>
+  </GridLayout>
+</Page>

apps/app/ui-tests-app/css/background-shorthand.ts

@@ -9,7 +9,9 @@ const tests = [
     { name: "black hex color only", background: "#000000" },
     { name: "yellow hex color only", background: "#ffff00" },
     { name: "blue color only", background: "blue" },
+
     { name: "repeat image only", background: "url(\"~/ui-tests-app/resources/images/icon.png\")" },
+    { name: "linear gradient red-blue only", background: "linear-gradient(to bottom, red, blue)"},
 
     { name: "[straight] image only, no-repeat ", background: "url(\"~/ui-tests-app/resources/images/icon.png\") no-repeat" },
     { name: "[straight] green color, image, no-repeat", background: "green url(\"~/ui-tests-app/resources/images/icon.png\") no-repeat" },
@@ -18,7 +20,7 @@ const tests = [
     { name: "[straight] orange hex color, image, no-repeat, position percents", background: "#F9791F url(\"~/ui-tests-app/resources/images/icon.png\") no-repeat 100% 100%" },
     { name: "[straight] green color, image, repeat-x, position percents", background: "green url(\"~/ui-tests-app/resources/images/icon.png\") repeat-x 100% 100%" },
     { name: "[straight] blue color, image, repeat-x, position", background: "blue url(\"~/ui-tests-app/resources/images/icon.png\") repeat-x 150 150" },
-    
+
     { name: "[shuffle] no-repeat, image only", background: "no-repeat url(\"~/ui-tests-app/resources/images/icon.png\")" },
     { name: "[shuffle] no-repeat, green color, image, ", background: "no-repeat green url(\"~/ui-tests-app/resources/images/icon.png\")" },
     { name: "[shuffle] yellow hex color, position pixels, image, no-repeat", background: "#ffff00 200px 200px url(\"~/ui-tests-app/resources/images/icon.png\") no-repeat" },

apps/app/ui-tests-app/css/gradient-border.css

@@ -0,0 +1,77 @@
+StackLayout {
+    width: 80;
+    height: 80;
+    background: linear-gradient(to top, green, blue);
+}
+
+#s0 {
+    border-width: 5;
+}
+
+#s1 {
+    border-width: 5; border-color: red;
+}
+
+#s2 {
+    border-width: 5; border-color: red red red green;
+}
+
+#s3 {
+    border-width: 5; border-color: red; border-radius: 5;
+}
+
+#s4 {
+    border-width: 5; border-color: red; border-radius: 50;
+}
+
+#s5 {
+    border-width: 5 10 15 20; border-color: red;
+}
+
+#s6 {
+    border-width: 5; border-color: red green blue yellow;
+}
+
+#s7 {
+    border-width: 5 10 15 20; border-color: red green blue yellow;
+}
+
+#s8 {
+    border-width: 5 10; border-color: red green;
+}
+
+#s9 {
+    border-width: 15 10 5; border-color: red green blue;
+}
+
+#s10 {
+    border-width: 5 0; border-color: black;
+}
+
+#s11 {
+    background-color: magenta;
+}
+
+#s12 {
+    border-width: 5 10 15 20; border-color: red green blue yellow; border-radius: 5 10 15 20;
+}
+
+#s13 {
+    border-width: 5 10 15 20; border-color: red green blue yellow; border-radius: 5;
+}
+
+#s14 {
+    border-width: 5 10 15 20; border-color: red green blue yellow; background-color: magenta;
+}
+
+#s15 {
+    border-width: 5 10 15 20; border-color: red green blue yellow; background-image: url('~/ui-tests-app/resources/images/test2.png');
+}
+
+#s16 {
+    border-width: 5; border-color: red; padding: 5;
+}
+
+#s17 {
+    border-width: 5 6 7 8; border-color: red green blue yellow; padding: 5 6 7 8;
+}

apps/app/ui-tests-app/css/gradient-border.xml

@@ -0,0 +1,22 @@
+<Page>
+    <GridLayout rows="*,*,*,*,*,*" columns="*,*,*">
+        <StackLayout  id="s0" row="0" col="0"/>
+        <StackLayout  id="s1" row="0" col="1"/>
+        <StackLayout  id="s2" row="0" col="2"/>
+        <StackLayout  id="s3" row="1" col="0"/>
+        <StackLayout  id="s4" row="1" col="1"/>
+        <StackLayout  id="s5" row="1" col="2"/>
+        <StackLayout  id="s6" row="2" col="0"/>
+        <StackLayout  id="s7" row="2" col="1"/>
+        <StackLayout  id="s8" row="2" col="2"/>
+        <StackLayout  id="s9" row="3" col="0"/>
+        <StackLayout id="s10" row="3" col="1"/>
+        <StackLayout id="s11" row="3" col="2"/>
+        <StackLayout id="s12" row="4" col="0"/>
+        <StackLayout id="s13" row="4" col="1"/>
+        <StackLayout id="s14" row="4" col="2"/>
+        <StackLayout id="s15" row="5" col="0"/>
+        <StackLayout id="s16" row="5" col="1"/>
+        <StackLayout id="s17" row="5" col="2"/>
+    </GridLayout>
+</Page>

apps/app/ui-tests-app/css/main-page.ts

@@ -30,6 +30,7 @@ export function loadExamples() {
     examples.set("label-border", "css/label-border");
     examples.set("text-view-border", "css/text-view-border");
     examples.set("image-border", "css/image-border");
+    examples.set("gradient-border", "css/gradient-border");
     examples.set("layouts-border-overlap", "css/layouts-border-overlap");
     examples.set("measure-tests", "css/measure-tests");
     examples.set("all-uniform-border", "css/all-uniform-border");
@@ -41,5 +42,6 @@ export function loadExamples() {
     examples.set("non-uniform-radius", "css/non-uniform-radius");
     examples.set("missing-background-image", "css/missing-background-image");
     examples.set("background-shorthand", "css/background-shorthand");
+    examples.set("background-image-linear-gradient", "css/background-image-linear-gradient");
     return examples;
 }