太平道教谁创立,葫芦岛电影院,九道湾大峡谷
这两天学习了ios屏幕亮度和闪光灯控制，所以，今天添加一点小笔记。
所用涉及框架：avfoundation框架和imageio
读取屏幕亮度：[uiscreen mainscreen].brightness;
设置屏幕亮度：[[uiscreen mainscreen] setbrightness:0.5];
获取环境亮度主要代码：
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- (void)gettorch {
avcapturedevice *device = [avcapturedevice defaultdevicewithmediatype:avmediatypevideo];
avcapturedeviceinput *input = [[avcapturedeviceinput alloc]initwithdevice:device error:nil];
avcapturevideodataoutput *output = [[avcapturevideodataoutput alloc] init];
[output setsamplebufferdelegate:self queue:dispatch_get_main_queue()];
self.session = [[avcapturesession alloc]init];
[self.session setsessionpreset:avcapturesessionpresethigh];
if ([self.session canaddinput:input]) {
[self.session addinput:input];
}
if ([self.session canaddoutput:output]) {
[self.session addoutput:output];
}
[self.session startrunning];
}
- (void)captureoutput:(avcaptureoutput*)captureoutput didoutputsamplebuffer:(cmsamplebufferref)samplebuffer fromconnection:(avcaptureconnection*)connection {
cfdictionaryref metadatadict =cmcopydictionaryofattachments(null,samplebuffer,
kcmattachmentmode_shouldpropagate);
nsdictionary *metadata = [[nsmutabledictionary alloc] initwithdictionary:
(__bridgensdictionary*)metadatadict];
cfrelease(metadatadict);
nsdictionary *exifmetadata = [[metadata objectforkey:(nsstring*)kcgimagepropertyexifdictionary] mutablecopy];
float brightnessvalue = [[exifmetadata objectforkey:(nsstring*)kcgimagepropertyexifbrightnessvalue] floatvalue];
nslog(@"%f",brightnessvalue);
// 根据brightnessvalue的值来打开和关闭闪光灯
avcapturedevice*device = [avcapturedevice defaultdevicewithmediatype:avmediatypevideo];
bool result = [device hastorch];// 判断设备是否有闪光灯
if((brightnessvalue <0) && result) {
// 打开闪光灯
[device lockforconfiguration:nil];
[device settorchmode:avcapturetorchmodeon];//开
[device unlockforconfiguration];
}else if((brightnessvalue >0) && result) {
// 关闭闪光灯
[device lockforconfiguration:nil];
[device settorchmode:avcapturetorchmodeoff];//关
[device unlockforconfiguration];
}
}
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