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Add perspective transform support on Android #11713

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satya164 wants to merge 1 commit into from
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Add perspective transform support on Android #11713

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2 changes: 1 addition & 1 deletion Examples/UIExplorer/js/TransformExample.js
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Original file line number Diff line number Diff line change
Expand Up @@ -211,7 +211,7 @@ exports.title = 'Transforms';
exports.description = 'View transforms';
exports.examples = [
{
title: 'Perspective',
title: 'Perspective, Rotate, Animation',
description: 'perspective: 850, rotateX: Animated.timing(0 -> 360)',
render(): React.Element<any> { return <Flip />; }
},
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22 changes: 20 additions & 2 deletions ReactAndroid/src/main/java/com/facebook/react/uimanager/BaseViewManager.java
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Expand Up @@ -5,8 +5,6 @@
import android.graphics.Color;
import android.os.Build;
import android.view.View;
import android.view.ViewGroup;

import com.facebook.react.bridge.ReadableArray;
import com.facebook.react.uimanager.annotations.ReactProp;

Expand Down Expand Up @@ -35,6 +33,9 @@ public abstract class BaseViewManager<T extends View, C extends LayoutShadowNode
private static final String PROP_TRANSLATE_X = "translateX";
private static final String PROP_TRANSLATE_Y = "translateY";

private static final int PERSPECTIVE_ARRAY_INVERTED_CAMERA_DISTANCE_INDEX = 2;
private static final float CAMERA_DISTANCE_NORMALIZATION_MULTIPLIER = 5;

/**
* Used to locate views in end-to-end (UI) tests.
*/
Expand Down Expand Up @@ -165,6 +166,22 @@ private static void setTransformProperty(View view, ReadableArray transforms) {
view.setRotationY((float) sMatrixDecompositionContext.rotationDegrees[1]);
view.setScaleX((float) sMatrixDecompositionContext.scale[0]);
view.setScaleY((float) sMatrixDecompositionContext.scale[1]);

double[] perspectiveArray = sMatrixDecompositionContext.perspective;

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@wcandillon wcandillon Nov 13, 2018

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When no perspective is set, on Android, you still see some perspective when doing "3d transformation" while on iOS it show as expected. Therefore you always get a different result on iOS and Android when setting perspective yourself. Do you see what I mean? I could provide some examples.

I would like to know what is the default perspective an android so I can adjust the transformation correctly for android.

Thank you so much for your great work, really appreciate it.

if (perspectiveArray.length > PERSPECTIVE_ARRAY_INVERTED_CAMERA_DISTANCE_INDEX) {
float invertedCameraDistance = (float) perspectiveArray[PERSPECTIVE_ARRAY_INVERTED_CAMERA_DISTANCE_INDEX];
if (invertedCameraDistance < 0) {
float cameraDistance = -1 / invertedCameraDistance;
float scale = DisplayMetricsHolder.getScreenDisplayMetrics().density;

// The following converts the matrix's perspective to a camera distance
// such that the camera perspective looks the same on Android and iOS
float normalizedCameraDistance = scale * cameraDistance * CAMERA_DISTANCE_NORMALIZATION_MULTIPLIER;

view.setCameraDistance(normalizedCameraDistance);
}
}
}

private static void resetTransformProperty(View view) {
Expand All @@ -175,5 +192,6 @@ private static void resetTransformProperty(View view) {
view.setRotationY(0);
view.setScaleX(1);
view.setScaleY(1);
view.setCameraDistance(0);
}
}