I want to display grid line like the one which appears when a camera is open.I am using AVCaptureManager.Should i use core graphics to draw grid lines?what is the size of those grid lines?
thanks
Tap on Settings. c). Select and tap on Grid lines switch to activate it.
You can indeed add a custom view as an overlay over your camera view to draw the grid using QuartzCore.
That is how I did it in my app Subvision:
The code I use to draw it (note: my grid is adjustable so it's can be 10x10, 2x2 etc):
// -------------------------------------------------------------------------------
// Used for drawing the grids ontop of the view port
// -------------------------------------------------------------------------------
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 0.5);
CGContextSetStrokeColorWithColor(context, [UIColor whiteColor].CGColor);
// ---------------------------
// Drawing column lines
// ---------------------------
// calculate column width
CGFloat columnWidth = self.frame.size.width / (self.numberOfColumns + 1.0);
for(int i = 1; i <= self.numberOfColumns; i++)
{
CGPoint startPoint;
CGPoint endPoint;
startPoint.x = columnWidth * i;
startPoint.y = 0.0f;
endPoint.x = startPoint.x;
endPoint.y = self.frame.size.height;
CGContextMoveToPoint(context, startPoint.x, startPoint.y);
CGContextAddLineToPoint(context, endPoint.x, endPoint.y);
CGContextStrokePath(context);
}
// ---------------------------
// Drawing row lines
// ---------------------------
// calclulate row height
CGFloat rowHeight = self.frame.size.height / (self.numberOfRows + 1.0);
for(int j = 1; j <= self.numberOfRows; j++)
{
CGPoint startPoint;
CGPoint endPoint;
startPoint.x = 0.0f;
startPoint.y = rowHeight * j;
endPoint.x = self.frame.size.width;
endPoint.y = startPoint.y;
CGContextMoveToPoint(context, startPoint.x, startPoint.y);
CGContextAddLineToPoint(context, endPoint.x, endPoint.y);
CGContextStrokePath(context);
}
}
In my GridView class, I have defined 2 properties numberOfRows and numberOfColumns:
#import <UIKit/UIKit.h>
@interface GridView : UIView
@property (nonatomic, assign) int numberOfColumns;
@property (nonatomic, assign) int numberOfRows;
@end
Doing so means I can modify these two values and have infinitely adjustable grid subdivisions.
Create a UIImageView to use for the cameraOverlayView.
Use UIImagePickerController and an image as your 'grid lines'. When making your grid line image file, be sure to use a transparent background - not opaque white.
UIImageView *overlayImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"overlay.png"]];
CGRect overlayRect = CGRectMake(0, 0, overlayImage.image.size.width, overlayImage.image.size.height);
[overlayImage setFrame:overlayRect];
[yourImagePickerController setCameraOverlayView:overlayImage];
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