Detailed description of automatically calculated rows for ios label and high description of ioslabel rows

Detailed description of automatically calculated rows for ios label and high description of ioslabel rows

Automatically calculates the main invocation system of the Row Height in OC.

-(-- Attributes :( CGSize) size options :( optional) options attributes :( nullable NSDictionary <NSString *, id> *) attributes context :( nullable NSStringDrawingContext *) context NS_AVAILABLE (10_11, 7_0 );

In different ios systems, the height and size of the same font are different. Therefore, you cannot set a specific height value.

Solution:

    label.text = @"xijoaiogioaiogioioaig";    label.numberOfLines = 2;    NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc]init];    style.maximumLineHeight = 20;    style.minimumLineHeight = 20;    CGRect rect = [label.text boundingRectWithSize:CGSizeMake(Screen_W - 125, 20*2) options: NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName:_comName.font,NSParagraphStyleAttributeName:style} context:nil];    _height = rect.size.height;

 

 

 

The following is a detailed description of this method.

Size: label or text display width and height. Generally, when the width is calculated automatically, if the width is fixed to a value of 100, it is set to CGSizeMake (100, MAXFLOAT) if the height is fixed to a value of 100, it is set to CGSizeMake (MAXFLOAT, 100). If both width and height are determined, they are set to specific values.

 

Options:

Additional options for text painting.
There are four types:
1.NSStringDrawingTruncatesLastVisibleLine
2.NSStringDrawingUsesLineFragmentOrigin
3.NSStringDrawingUsesFontLeading
4.NSStringDrawingUsesDeviceMetrics
GenerallyNSStringDrawingUsesLineFragmentOrigin,NSStringDrawingUsesLineFragmentOriginThe size of the entire text is calculated in the unit of a rectangle consisting of each line.

NSStringDrawingUsesFontLeading is the line spacing between fonts (leading, line spacing: the distance from the bottom of a line of text to the bottom of another line of text .) .

NSStringDrawingTruncatesLastVisibleLineOrNSStringDrawingUsesDeviceMetric, The text size is calculated in units of each word or font.

Attributes: which attribute of the basic text is used for calculation?

Context: text display pixels are generally transmitted to nil by default.

Note: When this method is used, the height of dynamic calculation cannot be set to adjustToSize (this method is limited to one row)