react-native/Libraries/Image/RCTImageView.m

340 lines
9.9 KiB
Objective-C

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
#import "RCTImageView.h"
#import "RCTBridge.h"
#import "RCTConvert.h"
#import "RCTEventDispatcher.h"
#import "RCTImageLoader.h"
#import "RCTImageSource.h"
#import "RCTImageUtils.h"
#import "RCTUtils.h"
#import "RCTImageBlurUtils.h"
#import "UIView+React.h"
/**
* Determines whether an image of `currentSize` should be reloaded for display
* at `idealSize`.
*/
static BOOL RCTShouldReloadImageForSizeChange(CGSize currentSize, CGSize idealSize)
{
static const CGFloat upscaleThreshold = 1.2;
static const CGFloat downscaleThreshold = 0.5;
CGFloat widthMultiplier = idealSize.width / currentSize.width;
CGFloat heightMultiplier = idealSize.height / currentSize.height;
return widthMultiplier > upscaleThreshold || widthMultiplier < downscaleThreshold ||
heightMultiplier > upscaleThreshold || heightMultiplier < downscaleThreshold;
}
@interface RCTImageView ()
@property (nonatomic, copy) RCTDirectEventBlock onLoadStart;
@property (nonatomic, copy) RCTDirectEventBlock onProgress;
@property (nonatomic, copy) RCTDirectEventBlock onError;
@property (nonatomic, copy) RCTDirectEventBlock onLoad;
@property (nonatomic, copy) RCTDirectEventBlock onLoadEnd;
@end
@implementation RCTImageView
{
__weak RCTBridge *_bridge;
CGSize _targetSize;
/**
* A block that can be invoked to cancel the most recent call to -reloadImage,
* if any.
*/
RCTImageLoaderCancellationBlock _reloadImageCancellationBlock;
}
- (instancetype)initWithBridge:(RCTBridge *)bridge
{
if ((self = [super init])) {
_bridge = bridge;
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center addObserver:self
selector:@selector(clearImageIfDetached)
name:UIApplicationDidReceiveMemoryWarningNotification
object:nil];
[center addObserver:self
selector:@selector(clearImageIfDetached)
name:UIApplicationDidEnterBackgroundNotification
object:nil];
}
return self;
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
RCT_NOT_IMPLEMENTED(- (instancetype)init)
- (void)updateImage
{
UIImage *image = self.image;
if (!image) {
return;
}
// Apply rendering mode
if (_renderingMode != image.renderingMode) {
image = [image imageWithRenderingMode:_renderingMode];
}
if (_resizeMode == RCTResizeModeRepeat) {
image = [image resizableImageWithCapInsets:_capInsets resizingMode:UIImageResizingModeTile];
} else if (!UIEdgeInsetsEqualToEdgeInsets(UIEdgeInsetsZero, _capInsets)) {
// Applying capInsets of 0 will switch the "resizingMode" of the image to "tile" which is undesired
image = [image resizableImageWithCapInsets:_capInsets resizingMode:UIImageResizingModeStretch];
}
// Apply trilinear filtering to smooth out mis-sized images
self.layer.minificationFilter = kCAFilterTrilinear;
self.layer.magnificationFilter = kCAFilterTrilinear;
super.image = image;
}
- (void)setImage:(UIImage *)image
{
image = image ?: _defaultImage;
if (image != super.image) {
super.image = image;
[self updateImage];
}
}
- (void)setBlurRadius:(CGFloat)blurRadius
{
if (blurRadius != _blurRadius) {
_blurRadius = blurRadius;
[self reloadImage];
}
}
- (void)setCapInsets:(UIEdgeInsets)capInsets
{
if (!UIEdgeInsetsEqualToEdgeInsets(_capInsets, capInsets)) {
if (UIEdgeInsetsEqualToEdgeInsets(_capInsets, UIEdgeInsetsZero) ||
UIEdgeInsetsEqualToEdgeInsets(capInsets, UIEdgeInsetsZero)) {
_capInsets = capInsets;
// Need to reload image when enabling or disabling capInsets
[self reloadImage];
} else {
_capInsets = capInsets;
[self updateImage];
}
}
}
- (void)setRenderingMode:(UIImageRenderingMode)renderingMode
{
if (_renderingMode != renderingMode) {
_renderingMode = renderingMode;
[self updateImage];
}
}
- (void)setSource:(RCTImageSource *)source
{
if (![source isEqual:_source]) {
_source = source;
[self reloadImage];
}
}
- (BOOL)sourceNeedsReload
{
// If capInsets are set, image doesn't need reloading when resized
return UIEdgeInsetsEqualToEdgeInsets(_capInsets, UIEdgeInsetsZero);
}
- (void)setResizeMode:(RCTResizeMode)resizeMode
{
if (_resizeMode != resizeMode) {
_resizeMode = resizeMode;
if (_resizeMode == RCTResizeModeRepeat) {
// Repeat resize mode is handled by the UIImage. Use scale to fill
// so the repeated image fills the UIImageView.
self.contentMode = UIViewContentModeScaleToFill;
} else {
self.contentMode = (UIViewContentMode)resizeMode;
}
if ([self sourceNeedsReload]) {
[self reloadImage];
}
}
}
- (void)cancelImageLoad
{
RCTImageLoaderCancellationBlock previousCancellationBlock = _reloadImageCancellationBlock;
if (previousCancellationBlock) {
previousCancellationBlock();
_reloadImageCancellationBlock = nil;
}
}
- (void)clearImage
{
[self cancelImageLoad];
[self.layer removeAnimationForKey:@"contents"];
self.image = nil;
}
- (void)clearImageIfDetached
{
if (!self.window) {
[self clearImage];
}
}
- (void)reloadImage
{
[self cancelImageLoad];
if (_source && self.frame.size.width > 0 && self.frame.size.height > 0) {
if (_onLoadStart) {
_onLoadStart(nil);
}
RCTImageLoaderProgressBlock progressHandler = nil;
if (_onProgress) {
progressHandler = ^(int64_t loaded, int64_t total) {
self->_onProgress(@{
@"loaded": @((double)loaded),
@"total": @((double)total),
});
};
}
CGSize imageSize = self.bounds.size;
CGFloat imageScale = RCTScreenScale();
if (!UIEdgeInsetsEqualToEdgeInsets(_capInsets, UIEdgeInsetsZero)) {
// Don't resize images that use capInsets
imageSize = CGSizeZero;
imageScale = _source.scale;
}
RCTImageSource *source = _source;
CGFloat blurRadius = _blurRadius;
__weak RCTImageView *weakSelf = self;
_reloadImageCancellationBlock =
[_bridge.imageLoader loadImageWithURLRequest:_source.request
size:imageSize
scale:imageScale
clipped:NO
resizeMode:_resizeMode
progressBlock:progressHandler
completionBlock:^(NSError *error, UIImage *loadedImage) {
RCTImageView *strongSelf = weakSelf;
void (^setImageBlock)(UIImage *) = ^(UIImage *image) {
if (![source isEqual:strongSelf.source]) {
// Bail out if source has changed since we started loading
return;
}
if (image.reactKeyframeAnimation) {
[strongSelf.layer addAnimation:image.reactKeyframeAnimation forKey:@"contents"];
} else {
[strongSelf.layer removeAnimationForKey:@"contents"];
strongSelf.image = image;
}
if (error) {
if (strongSelf->_onError) {
strongSelf->_onError(@{ @"error": error.localizedDescription });
}
} else {
if (strongSelf->_onLoad) {
strongSelf->_onLoad(nil);
}
}
if (strongSelf->_onLoadEnd) {
strongSelf->_onLoadEnd(nil);
}
};
if (blurRadius > __FLT_EPSILON__) {
// Blur on a background thread to avoid blocking interaction
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
UIImage *image = RCTBlurredImageWithRadius(loadedImage, blurRadius);
RCTExecuteOnMainQueue(^{
setImageBlock(image);
});
});
} else {
// No blur, so try to set the image on the main thread synchronously to minimize image
// flashing. (For instance, if this view gets attached to a window, then -didMoveToWindow
// calls -reloadImage, and we want to set the image synchronously if possible so that the
// image property is set in the same CATransaction that attaches this view to the window.)
RCTExecuteOnMainQueue(^{
setImageBlock(loadedImage);
});
}
}];
} else {
[self clearImage];
}
}
- (void)reactSetFrame:(CGRect)frame
{
[super reactSetFrame:frame];
if (!self.image || self.image == _defaultImage) {
_targetSize = frame.size;
[self reloadImage];
} else if ([self sourceNeedsReload]) {
CGSize imageSize = self.image.size;
CGSize idealSize = RCTTargetSize(imageSize, self.image.scale, frame.size,
RCTScreenScale(), (RCTResizeMode)self.contentMode, YES);
if (RCTShouldReloadImageForSizeChange(imageSize, idealSize)) {
if (RCTShouldReloadImageForSizeChange(_targetSize, idealSize)) {
RCTLogInfo(@"[PERF IMAGEVIEW] Reloading image %@ as size %@", _source.request.URL.absoluteString, NSStringFromCGSize(idealSize));
// If the existing image or an image being loaded are not the right
// size, reload the asset in case there is a better size available.
_targetSize = idealSize;
[self reloadImage];
}
} else {
// Our existing image is good enough.
[self cancelImageLoad];
_targetSize = imageSize;
}
}
}
- (void)didMoveToWindow
{
[super didMoveToWindow];
if (!self.window) {
// Cancel loading the image if we've moved offscreen. In addition to helping
// prioritise image requests that are actually on-screen, this removes
// requests that have gotten "stuck" from the queue, unblocking other images
// from loading.
[self cancelImageLoad];
} else if (!self.image || self.image == _defaultImage) {
[self reloadImage];
}
}
@end