Can someone tell me how to read and edit the EXIF data on a photo in B4i?
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iOS Question EXIF data
- Thread starter hzchrisfang
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Hi,
The values are always 1
, maybe somebody can do something with that ...
B4X:
Dim NaObj As NativeObject = Me
Dim EXIFMap As Map = NaObj.RunMethod("GetEXIF::",Array("PNG",LoadBitmap(File.DirAssets,"p2.png")))
For Each key In EXIFMap.Keys
Log(key & ": " & EXIFMap.Get(key))
Next
#If OBJC
#import <ImageIO/ImageIO.h>
-(B4IMap*) GetEXIF:(NSString *) Type :(UIImage *) Image{
NSDictionary* EXIFDic = nil;
NSData* ImageData;
if ([Type isEqualToString:@"JPEG"]){
ImageData = UIImageJPEGRepresentation(Image, 0.0);
}else if ([Type isEqualToString:@"PNG"]){
ImageData = UIImagePNGRepresentation(Image);
}
CGImageSourceRef source = CGImageSourceCreateWithData((CFDataRef)ImageData, NULL);
if (source){
CFDictionaryRef MetadataRef = CGImageSourceCopyPropertiesAtIndex(source,0,NULL);
if (MetadataRef){
EXIFDic = [NSDictionary dictionaryWithDictionary : (__bridge NSDictionary *)MetadataRef];
CFRelease (MetadataRef);
}
CFRelease(source);
source = nil;
}
NSArray * Keys = [EXIFDic allKeys];
NSArray * Values = [EXIFDic allValues];
B4IMap * Map;
Map = [B4IMap new];
[Map Initialize];
int i;
for (i = 0; i < [Keys count]; i++){
[Map Put:(NSObject*)([Keys objectAtIndex:i]) :(NSObject*)([Values objectAtIndex:i])];
}
return Map;
}
#End IfThe values are always 1
, maybe somebody can do something with that ...
Last edited:
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Thank you JanPRO!
I can get some values:
but how to write exif data into a photo?
I can get some values:
B4X:
{JFIF}: {
DensityUnit = 0;
JFIFVersion = (
1,
0,
1
);
XDensity = 72;
YDensity = 72;
}
Orientation: 1
PixelWidth: 1920
{TIFF}: {
Orientation = 1;
}
ColorModel: RGB
{Exif}: {
ColorSpace = 1;
PixelXDimension = 1920;
PixelYDimension = 1080;
}
Depth: 8
PixelHeight: 1080but how to write exif data into a photo?
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Hi, based on http://stackoverflow.com/questions/...tadata-exif-gps-tiff-in-iphones-photo-library:
I have not tested yet. It should work ....
B4X:
Dim NaObj As NativeObject = Me
'Save to PhotoAlbum
NaObj.RunMethod("SetGPS:Type:GPSLatitude:GPSLongitude:GPSLatitudeRef:GPSLongitudeRef:DataPath:WriteInPhotoAlbum:",Array(LoadBitmap(File.DirAssets,"x.jpg"),"JPEG",1.1,2.2,"lat_ref","lon_ref",Null,True))
'Save to Directory
NaObj.RunMethod("SetGPS:Type:GPSLatitude:GPSLongitude:GPSLatitudeRef:GPSLongitudeRef:DataPath:WriteInPhotoAlbum:",Array(LoadBitmap(File.DirAssets,"x.jpg"),"JPEG",1.1,2.2,"lat_ref","lon_ref",File.Combine(File.DirDocuments,"x.jpeg"),False))
End Sub
#If OBJC
#import <ImageIO/ImageIO.h>
#import <AssetsLibrary/AssetsLibrary.h>
- (void)SetGPS:(UIImage *)Image Type:(NSString*)Type GPSLatitude:(float)GPSLatitude GPSLongitude:(float)GPSLongitude GPSLatitudeRef:(NSString*)GPSLatitudeRef GPSLongitudeRef:(NSString*)GPSLongitudeRef DataPath:(NSString*)DataPath WriteInPhotoAlbum:(BOOL)WriteInPhotoAlbum {
NSData* ImageData;
if ([Type isEqualToString:@"JPEG"]){
ImageData = UIImageJPEGRepresentation(Image, 1.0);
}else if ([Type isEqualToString:@"PNG"]){
ImageData = UIImagePNGRepresentation(Image);
}
CGImageSourceRef source = CGImageSourceCreateWithData((CFDataRef)ImageData, NULL);
NSDictionary *metadata = (__bridge NSDictionary *) CGImageSourceCopyPropertiesAtIndex(source, 0, NULL);
NSMutableDictionary *metadataAsMutable = [metadata mutableCopy];
NSMutableDictionary *GPSDictionary = [[metadataAsMutable objectForKey:(NSString *)kCGImagePropertyGPSDictionary]mutableCopy];
if(!GPSDictionary)
{
NSDictionary * dictionary = nil;
GPSDictionary = [NSMutableDictionary dictionary];
}
[GPSDictionary setValue:[NSNumber numberWithFloat:GPSLatitude] forKey:(NSString*)kCGImagePropertyGPSLatitude];
[GPSDictionary setValue:[NSNumber numberWithFloat:GPSLongitude] forKey:(NSString*)kCGImagePropertyGPSLongitude];
[GPSDictionary setValue:GPSLatitudeRef forKey:(NSString*)kCGImagePropertyGPSLatitudeRef];
[GPSDictionary setValue:GPSLongitudeRef forKey:(NSString*)kCGImagePropertyGPSLongitudeRef];
[metadataAsMutable setObject:GPSDictionary forKey:(NSString *)kCGImagePropertyGPSDictionary];
if (WriteInPhotoAlbum == YES){
ALAssetsLibrary *library = [ALAssetsLibrary alloc];
ALAssetsLibraryWriteImageCompletionBlock imageWriteCompletionBlock =
^(NSURL *newURL, NSError *error) {
if (error) {
NSLog( @"Error writing image with metadata to Photo Library: %@", error );
} else {
NSLog( @"Wrote image %@ with metadata %@ to Photo Library",newURL,metadataAsMutable);
}
};
[library writeImageToSavedPhotosAlbum:Image.CGImage
metadata:metadataAsMutable
completionBlock:imageWriteCompletionBlock];
}else{
CFStringRef UTI = CGImageSourceGetType(source);
NSMutableData *dest_data = [NSMutableData data];
CGImageDestinationRef destination = CGImageDestinationCreateWithData((CFMutableDataRef) dest_data, UTI, 1, NULL);
if(!destination){
NSLog(@"--------- Could not create image destination---------");
}
CGImageDestinationAddImageFromSource(destination, source, 0, (CFDictionaryRef) metadataAsMutable);
BOOL success = NO;
success = CGImageDestinationFinalize(destination);
if(!success){
NSLog(@"-------- could not create data from image destination----------");
}else{
[dest_data writeToFile:DataPath atomically:YES];
NSLog( @"Wrote image to %@ with metadata %@",DataPath,metadataAsMutable);
}
}
}
#End If
Last edited:
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B4X:
'Orientations:
'Up = 0
'Down = 1
'Left = 2
'Right = 3
'UpMirrored = 4
'DownMirrored = 5
'LeftMirrored = 6
'RightMirrored = 7
Sub SetOrientation(b As Bitmap, O As Int) As Bitmap
Dim NaObj2 As NativeObject = b
Dim NaObj As NativeObject
Return NaObj.Initialize("UIImage").RunMethod("imageWithCGImage:scale:orientation:",Array(NaObj2.RunMethod("CGImage",Null),NaObj2.RunMethod("scale",Null),o))
End Sub
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I have never written that I can't do it
Maybe I am going to write a class, but a library is not needed here.
Jan
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Try doing it this way. Just query theExifMap for the values you require. (You can also use theMetaMap for other useful information such as getting the dimensions of an image without having to load the image.)
B4X:
Dim theMetaMap As Map=getImageMetaData(filename)
Dim theExifMap As Map=theMetaMap.get("{Exif}")
public Sub getImageMetaData(filename As String) As Map
Dim nome As NativeObject=Me
Dim imageMetaData As Object = nome.RunMethod("getImageMetaData:",Array(filename))
Return NSDictionaryToMap(imageMetaData)
End Sub
Sub NSDictionaryToMap(Dictionary As Object) As Map
Dim NewMap As NativeObject
NewMap = NewMap.Initialize("B4IMap").RunMethod("convertToMap:",Array(Dictionary))
Return NewMap
End Sub
#if OBJC
#import <ImageIO/ImageIO.h>
- (NSDictionary*) getImageMetaData : (NSString*) file
{
NSDictionary* dic = nil;
NSURL *imageFileURL = [NSURL fileURLWithPath: file];
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((CFURLRef)imageFileURL, nil);
if (imageSource == nil) {
return nil;
}
CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, nil);
CFRelease(imageSource);
if (imageProperties != nil) {
if ( imageProperties )
{
NSDictionary* immutableImageProerties = (__bridge NSDictionary *)imageProperties;
if ( immutableImageProerties )
{
dic =
[ NSDictionary dictionaryWithDictionary : (__bridge NSDictionary *)imageProperties ];
}
CFRelease (imageProperties);
}
}
return dic;
}
#End If
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Hi,
I need to set GPS coordinates in a JPEG file, but it seems this code is not working on my iOS 12 device. Am I missing somthing ?
It seems it just does nothing: the image is unaffected.
UPDATE: it seems the GPS coordinates ARE bieng stored, but it seems there is no offset to it (or something) so that the properties of Windows does not show the coodinates, whereas a specialized application does
Thanks
Last edited:
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