Wie schreibe ich Text in Imageive-C (iOS)?
Ich möchte ein Bild wie folgt programmgesteuert machen:
Ich habe das obere Bild und den Text bei mir. Soll ich Text auf das Bild schreiben?
Ich möchte es zu einem vollständigen .png-Bild (Bild + Beschriftung) machen und es als Hintergrund für die Schaltfläche festlegen.
Zeichnen Sie Text in ein Bild und geben Sie das resultierende Bild zurück:
+(UIImage*) drawText:(NSString*) text
inImage:(UIImage*) image
atPoint:(CGPoint) point
{
UIFont *font = [UIFont boldSystemFontOfSize:12];
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
CGRect rect = CGRectMake(point.x, point.y, image.size.width, image.size.height);
[[UIColor whiteColor] set];
[text drawInRect:CGRectIntegral(rect) withFont:font];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
Verwendungszweck:
// note: replace "ImageUtils" with the class where you pasted the method above
UIImage *img = [ImageUtils drawText:@"Some text"
inImage:img
atPoint:CGPointMake(0, 0)];
Ändern Sie den Ursprung des Textes im Bild von 0,0 an einen beliebigen Punkt.
Fügen Sie vor der Zeile [[UIColor whiteColor] set]; Folgendes ein, um ein Rechteck aus einfarbiger Farbe hinter dem Text zu zeichnen:
[[UIColor brownColor] set];
CGContextFillRect(UIGraphicsGetCurrentContext(),
CGRectMake(0, (image.size.height-[text sizeWithFont:font].height),
image.size.width, image.size.height));
Ich verwende die Textgröße, um den Ursprung für das einfarbige Rechteck zu berechnen, aber Sie können ihn durch eine beliebige Zahl ersetzen.
Mein Beitrag zur ersten Antwort mit iOS 7-Support:
+(UIImage*) drawText:(NSString*) text
inImage:(UIImage*) image
atPoint:(CGPoint) point
{
UIGraphicsBeginImageContextWithOptions(image.size, YES, 0.0f);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
CGRect rect = CGRectMake(point.x, point.y, image.size.width, image.size.height);
[[UIColor whiteColor] set];
UIFont *font = [UIFont boldSystemFontOfSize:12];
if([text respondsToSelector:@selector(drawInRect:withAttributes:)])
{
//iOS 7
NSDictionary *att = @{NSFontAttributeName:font};
[text drawInRect:rect withAttributes:att];
}
else
{
//legacy support
[text drawInRect:CGRectIntegral(rect) withFont:font];
}
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
Hoffe das hilft
EDIT: änderte die UIGraphicsBeginImageContextWithOptions, um die Bildschirmskala zu handhaben. Thk @ SoftDesigner
Hier ist die Swift-Version.
func textToImage(drawText: NSString, inImage: UIImage, atPoint:CGPoint)->UIImage{
// Setup the font specific variables
var textColor: UIColor = UIColor.whiteColor()
var textFont: UIFont = UIFont(name: "Helvetica Bold", size: 12)!
//Setup the image context using the passed image.
UIGraphicsBeginImageContext(inImage.size)
//Setups up the font attributes that will be later used to dictate how the text should be drawn
let textFontAttributes = [
NSFontAttributeName: textFont,
NSForegroundColorAttributeName: textColor,
]
//Put the image into a rectangle as large as the original image.
inImage.drawInRect(CGRectMake(0, 0, inImage.size.width, inImage.size.height))
// Creating a point within the space that is as bit as the image.
var rect: CGRect = CGRectMake(atPoint.x, atPoint.y, inImage.size.width, inImage.size.height)
//Now Draw the text into an image.
drawText.drawInRect(rect, withAttributes: textFontAttributes)
// Create a new image out of the images we have created
var newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()
// End the context now that we have the image we need
UIGraphicsEndImageContext()
//And pass it back up to the caller.
return newImage
}
Um es anzurufen, übergeben Sie einfach ein Bild.
textToImage("000", inImage: UIImage(named:"thisImage.png")!, atPoint: CGPointMake(20, 20))
Die folgenden Links haben mir geholfen, dies klarer zu machen.
Swift - Zeichnen von Text mit drawInRect: withAttributes:
Wie schreibe ich in Objective-C (iOS) Text auf ein Bild?
Das ursprüngliche Ziel bestand darin, ein dynamisches Bild zu erstellen, das ich in AnnotaionView verwenden konnte, z. B. einen Preis an einer bestimmten Position auf einer Karte zu platzieren. Dies hat sich hervorragend bewährt. Ich hoffe, das hilft jemandem, der versucht, dasselbe zu tun.
nur iOS7.
Wasserzeichen in der rechten unteren Ecke.
@interface UIImage (DrawWatermarkText)
-(UIImage*)drawWatermarkText:(NSString*)text;
@end
@implementation UIImage (DrawWatermarkText)
-(UIImage*)drawWatermarkText:(NSString*)text {
UIColor *textColor = [UIColor colorWithWhite:0.5 alpha:1.0];
UIFont *font = [UIFont systemFontOfSize:50];
CGFloat paddingX = 20.f;
CGFloat paddingY = 20.f;
// Compute rect to draw the text inside
CGSize imageSize = self.size;
NSDictionary *attr = @{NSForegroundColorAttributeName: textColor, NSFontAttributeName: font};
CGSize textSize = [text sizeWithAttributes:attr];
CGRect textRect = CGRectMake(imageSize.width - textSize.width - paddingX, imageSize.height - textSize.height - paddingY, textSize.width, textSize.height);
// Create the image
UIGraphicsBeginImageContext(imageSize);
[self drawInRect:CGRectMake(0, 0, imageSize.width, imageSize.height)];
[text drawInRect:CGRectIntegral(textRect) withAttributes:attr];
UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resultImage;
}
@end
Verwendungszweck:
UIImage *image = [UIImage imageNamed:@"mona_Lisa"];
image = [image drawWatermarkText:@"Leonardo da Vinci"];
Ich habe so etwas gemacht! Nach Durchsuchen und Kombinieren einiger Beispiele.
Fügt den Text in die Mitte des Bildes ein und passt die Schrift ggf. an.
UIImage *myImage = [UIImage imageNamed:@"promoicon.png"];
UIGraphicsBeginImageContext(myImage.size);
[myImage drawInRect:CGRectMake(0,0,myImage.size.width,myImage.size.height)];
UITextView *myText = [[UITextView alloc] init];
myText.font = [UIFont fontWithName:@"TrebuchetMS-Bold" size:15.0f];
myText.textColor = [UIColor whiteColor];
myText.text = NSLocalizedString(@"promotionImageText", @"");
myText.backgroundColor = [UIColor clearColor];
CGSize maximumLabelSize = CGSizeMake(myImage.size.width,myImage.size.height);
CGSize expectedLabelSize = [myText.text sizeWithFont:myText.font
constrainedToSize:maximumLabelSize
lineBreakMode:UILineBreakModeWordWrap];
myText.frame = CGRectMake((myImage.size.width / 2) - (expectedLabelSize.width / 2),
(myImage.size.height / 2) - (expectedLabelSize.height / 2),
myImage.size.width,
myImage.size.height);
[[UIColor whiteColor] set];
[myText.text drawInRect:myText.frame withFont:myText.font];
UIImage *myNewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Ich habe eine vollständig angepasste Erweiterung für UIImage erstellt, um Wasserzeichen in Swift zu zeichnen:
extension UIImage{
enum WaterMarkCorner{
case TopLeft
case TopRight
case BottomLeft
case BottomRight
}
func waterMarkedImage(#waterMarkText:String, corner:WaterMarkCorner = .BottomRight, margin:CGPoint = CGPoint(x: 20, y: 20), waterMarkTextColor:UIColor = UIColor.whiteColor(), waterMarkTextFont:UIFont = UIFont.systemFontOfSize(20), backgroundColor:UIColor = UIColor.clearColor()) -> UIImage{
let textAttributes = [NSForegroundColorAttributeName:waterMarkTextColor, NSFontAttributeName:waterMarkTextFont]
let textSize = NSString(string: waterMarkText).sizeWithAttributes(textAttributes)
var textFrame = CGRectMake(0, 0, textSize.width, textSize.height)
let imageSize = self.size
switch corner{
case .TopLeft:
textFrame.Origin = margin
case .TopRight:
textFrame.Origin = CGPoint(x: imageSize.width - textSize.width - margin.x, y: margin.y)
case .BottomLeft:
textFrame.Origin = CGPoint(x: margin.x, y: imageSize.height - textSize.height - margin.y)
case .BottomRight:
textFrame.Origin = CGPoint(x: imageSize.width - textSize.width - margin.x, y: imageSize.height - textSize.height - margin.y)
}
/// Start creating the image with water mark
UIGraphicsBeginImageContext(imageSize)
self.drawInRect(CGRectMake(0, 0, imageSize.width, imageSize.height))
NSString(string: waterMarkText).drawInRect(textFrame, withAttributes: textAttributes)
let waterMarkedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return waterMarkedImage
}
}
Wie Sie sehen, habe ich einige Standardwerte für Attribute hinzugefügt, sodass Sie sie ignorieren können, wenn Sie keine Änderungen vornehmen müssen. Hier einige Beispiele, wie man es benutzt:
let watermark1 = image.waterMarkedImage(waterMarkText: "@yourapp")
let watermark2 = image.waterMarkedImage(waterMarkText: "your app name", corner: .TopRight, margin: CGPoint(x: 5, y: 5), waterMarkTextColor: UIColor.greenColor())
let watermark3 = image.waterMarkedImage(waterMarkText: "appName", waterMarkTextColor: UIColor.blackColor(), waterMarkTextFont: UIFont(name: "Helvatica", size: 25)!)
Swift 4.0 Version:
extension UIImage
{
enum WaterMarkCorner
{
case TopLeft
case TopRight
case BottomLeft
case BottomRight
}
func waterMarkedImage(text:String, corner:WaterMarkCorner = .BottomRight, margin:CGPoint = CGPoint(x: 20, y: 20), color:UIColor = UIColor.white, font:UIFont = UIFont.systemFont(ofSize: 20), background:UIColor = UIColor.clear) -> UIImage?
{
let attributes = [NSAttributedStringKey.foregroundColor: color, NSAttributedStringKey.font:font]
let textSize = NSString(string: text).size(withAttributes: attributes)
var frame = CGRect(x: 0, y: 0, width: textSize.width, height: textSize.height)
let imageSize = self.size
switch corner
{
case .TopLeft:
frame.Origin = margin
case .TopRight:
frame.Origin = CGPoint(x: imageSize.width - textSize.width - margin.x, y: margin.y)
case .BottomLeft:
frame.Origin = CGPoint(x: margin.x, y: imageSize.height - textSize.height - margin.y)
case .BottomRight:
frame.Origin = CGPoint(x: imageSize.width - textSize.width - margin.x, y: imageSize.height - textSize.height - margin.y)
}
// Start creating the image with water mark
UIGraphicsBeginImageContext(imageSize)
self.draw(in: CGRect(x: 0, y: 0, width: imageSize.width, height: imageSize.height))
NSString(string: text).draw(in: frame, withAttributes: attributes)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
}
Hier ist eine Swift-Version, die den Text im Bild richtig zentriert. Dies funktioniert mit Text in verschiedenen Größen.
func addTextToImage(text: NSString, inImage: UIImage, atPoint:CGPoint) -> UIImage{
// Setup the font specific variables
let textColor = YOURCOLOR
let textFont = YOUR SIZE
//Setups up the font attributes that will be later used to dictate how the text should be drawn
let textFontAttributes = [
NSFontAttributeName: textFont,
NSForegroundColorAttributeName: textColor,
]
// Create bitmap based graphics context
UIGraphicsBeginImageContextWithOptions(inImage.size, false, 0.0)
//Put the image into a rectangle as large as the original image.
inImage.drawInRect(CGRectMake(0, 0, inImage.size.width, inImage.size.height))
// Our drawing bounds
let drawingBounds = CGRectMake(0.0, 0.0, inImage.size.width, inImage.size.height)
let textSize = text.sizeWithAttributes([NSFontAttributeName:textFont])
let textRect = CGRectMake(drawingBounds.size.width/2 - textSize.width/2, drawingBounds.size.height/2 - textSize.height/2,
textSize.width, textSize.height)
text.drawInRect(textRect, withAttributes: textFontAttributes)
// Get the image from the graphics context
let newImag = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImag
}
Verwenden Sie diese Methode, um Ihr Textfeld mit ausgewählter Schriftart, Farbe und Größe zum Bild hinzuzufügen
//Method to add
- (UIImage *) addText:(UIImage *)img text:(NSString *)text
{
CGRect rect = CGRectMake(0,0, img.size.width, img.size.height);
// create a context according to image size
UIGraphicsBeginImageContext(rect.size);
// draw image
[img drawInRect:rect];
float fontSize = _txtvwEdit.font.pointSize*2;
NSLog(@"Original %f new %f",_txtvwEdit.font.pointSize,fontSize);
UIFont* font = [UIFont fontWithName:_txtvwEdit.font.fontName size:fontSize];
CGRect textRect = CGRectMake((_txtvwEdit.frame.Origin.x*2)-5,_txtvwEdit.frame.Origin.y*2,_txtvwEdit.frame.size.width*2,_txtvwEdit.frame.size.height*2);
if ([temparyGifframes count]>0)
{
font = [UIFont fontWithName:_txtvwEdit.font.fontName size:_txtvwEdit.font.pointSize];
textRect = CGRectMake(_txtvwEdit.frame.Origin.x,_txtvwEdit.frame.Origin.y ,_txtvwEdit.frame.size.width,_txtvwEdit.frame.size.height);
}
/// Make a copy of the default paragraph style
NSMutableParagraphStyle* paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
paragraphStyle.lineBreakMode = NSLineBreakByCharWrapping;
paragraphStyle.alignment = NSTextAlignmentLeft;
NSDictionary *attributes = @{ NSFontAttributeName: font, NSForegroundColorAttributeName: _txtvwEdit.textColor,NSParagraphStyleAttributeName: paragraphStyle };
// draw text
[text drawInRect:textRect withAttributes:attributes];
// get as image
UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
In Swift-3 von @Jano Antwort: -
func drawText(text:NSString ,image:UIImage ,point:CGPoint ) -> UIImage {
let font = UIFont.boldSystemFont(ofSize: 12)
UIGraphicsBeginImageContext(image.size)
image.draw(in:CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height) )
let rect = CGRect(x: point.x, y: point.y, width:image.size.width, height: image.size.height )
UIColor.white.set()
text.draw(in: rect.integral, withAttributes: [NSFontAttributeName : font])
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image!
}
Meine Funktion kann Textwasserzeichen mit 45- und 90-Grad-Drehungen hinzufügen
+(UIImage *)drawText:(NSString *)text diagonallyOnImage:(UIImage *)image rotation:(WatermarkRotation)rotation{
UIColor *textColor = [UIColor colorWithRed:255 green:0 blue:0 alpha:0.2];//[UIColor colorWithWhite:0.5 alpha:1.0];
UIFont *font = [UIFont systemFontOfSize:250];
// Compute rect to draw the text inside
NSDictionary *attr = @{NSForegroundColorAttributeName: textColor, NSFontAttributeName: font};
CGSize textSize = [text sizeWithAttributes:attr];
CGSize imageSize = image.size;
// Create a bitmap context into which the text will be rendered.
UIGraphicsBeginImageContext(textSize);
// Render the text
[text drawAtPoint:CGPointMake(0,0) withAttributes:attr];
// Retrieve the image
UIImage* img = UIGraphicsGetImageFromCurrentImageContext();
CGImageRef imageRef = [img CGImage];
CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef);
CGContextRef bitmap = CGBitmapContextCreate(NULL, textSize.width, textSize.width, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo);
switch (rotation) {
case WatermarkRotation90left:
CGContextRotateCTM (bitmap, DEGREES_RADIANS(-90));
CGContextTranslateCTM(bitmap, -textSize.width, 0);
break;
case WatermarkRotation90right:
CGContextRotateCTM (bitmap, DEGREES_RADIANS(90));
CGContextTranslateCTM(bitmap, 0, -textSize.width);
break;
case WatermarkRotation45ltr:
CGContextRotateCTM (bitmap, DEGREES_RADIANS(45));
CGContextTranslateCTM(bitmap, textSize.width/4, -textSize.width/2);
break;
case WatermarkRotation45rtl:
CGContextRotateCTM (bitmap, DEGREES_RADIANS(-45));
CGContextTranslateCTM(bitmap, -textSize.width/2, textSize.width/4);
break;
default:
break;
}
CGContextDrawImage(bitmap, CGRectMake(0, (textSize.width/2)-(textSize.height/2), textSize.width, textSize.height), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage* newImage = [UIImage imageWithCGImage:ref];
UIGraphicsBeginImageContext( imageSize );
// Use existing opacity as is
[image drawInRect:CGRectMake(0,0,imageSize.width,imageSize.height)];
if (rotation == WatermarkRotation90left) {
[newImage drawInRect:CGRectMake(-((textSize.width/2)-(textSize.height/2)),(imageSize.height/2)-(textSize.width/2),textSize.width,textSize.width) blendMode:kCGBlendModeNormal alpha:1.0];
}else if(rotation == WatermarkRotation90right){
[newImage drawInRect:CGRectMake((imageSize.width-textSize.width/2)-(textSize.height/2),(imageSize.height/2)-(textSize.width/2),textSize.width,textSize.width) blendMode:kCGBlendModeNormal alpha:1.0];
}else{
[newImage drawInRect:CGRectMake((imageSize.width/2)-(textSize.width/2),(imageSize.height/2)-(textSize.width/2),textSize.width,textSize.width) blendMode:kCGBlendModeNormal alpha:1.0];
}
UIImage *mergedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return mergedImage;
}
Enum für Rotation:
typedef enum:NSUInteger{
WatermarkRotation90left=1,
WatermarkRotation90right,
WatermarkRotation45ltr,
WatermarkRotation45rtl
}WatermarkRotation;
Hinweis: Verwenden Sie 0 zum Zeichnen eines Wasserzeichens in der Bildmitte (Standardfall der switch-Anweisung).
Fügen Sie dieses Makro für Grad zu Radiant hinzu:
#define DEGREES_RADIANS(angle) ((angle) / 180.0 * M_PI)
Hoffe das hilft !!!
In Anbetracht der Leistung sollten Sie häufige Aufrufe von -drawRect: vermeiden. Jede UIView wird mit einem CALayer gesichert, und Bilder bleiben erhalten, während der Layer-Inhalt im Speicher verbleibt, solange der CALayer in der Hierarchie bleibt. Dies bedeutet, dass die meisten Vorgänge, die Sie in einer Anwendung sehen, einschließlich Verschiebung, Drehung und Skalierung der Ansicht/Ebene , benötigen Sie keine redraw.Dies bedeutet, Sie können einen CATextLayer in UIImageView hinzufügen. Wenn Sie kein Bild mit Wasserzeichen benötigen . https://developer.Apple.com/library/ios/qa/ qa1708/_index.html
- (void)addText:(NSString *)text inImageView:(UIImageView *)imageView {
CATextLayer *textLayer = [CATextLayer layer];
UIFont *font = [UIFont systemFontOfSize:14.0f];
CGSize textSize = [text sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:14.0f]}];
textLayer.frame = CGRectMake((imageView.size.width - textSize.width)/2,
(imageView.size.height - textSize.height)/2,
textSize.width, textSize.height);;
textLayer.string = text;
textLayer.fontSize = font.pointSize;
[imageView.layer addSublayer:textLayer];
}
Swift 3-Version von @Hossam Ghareebs antwortete auf .__ und fügte die fehlende Integration des backgroundColor-Parameters hinzu:
enum WaterMarkCorner{
case TopLeft
case TopRight
case BottomLeft
case BottomRight
}
extension UIImage{
func waterMarkedImage(_ waterMarkText:String, corner:WaterMarkCorner = .TopRight, margin:CGPoint = CGPoint(x: 20, y: 20), waterMarkTextColor:UIColor = UIColor.black, waterMarkTextFont:UIFont = UIFont.systemFont(ofSize: 40), backgroundColor:UIColor = UIColor(white: 1.0, alpha: 0.5)) -> UIImage?{
let textAttributes = [NSForegroundColorAttributeName:waterMarkTextColor, NSFontAttributeName:waterMarkTextFont, NSBackgroundColorAttributeName: backgroundColor]
let textSize = NSString(string: waterMarkText).size(attributes: textAttributes)
var textFrame = CGRect(x:0, y:0, width:textSize.width, height:textSize.height)
let imageSize = self.size
switch corner{
case .TopLeft:
textFrame.Origin = margin
case .TopRight:
textFrame.Origin = CGPoint(x: imageSize.width - textSize.width - margin.x, y: margin.y)
case .BottomLeft:
textFrame.Origin = CGPoint(x: margin.x, y: imageSize.height - textSize.height - margin.y)
case .BottomRight:
textFrame.Origin = CGPoint(x: imageSize.width - textSize.width - margin.x, y: imageSize.height - textSize.height - margin.y)
}
/// Start creating the image with water mark
UIGraphicsBeginImageContext(imageSize)
self.draw(in: CGRect(x:0, y:0, width:imageSize.width, height:imageSize.height))
NSString(string: waterMarkText).draw(in: textFrame, withAttributes: textAttributes)
let waterMarkedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return waterMarkedImage
}
}
Swift 3
extension UIImage {
func textToImage(drawText: NSString, atPoint:CGPoint) -> UIImage? {
// Setup the font specific variables
let textColor: UIColor = UIColor.white
let textFont: UIFont = UIFont(name: "Helvetica Bold", size: 12)!
//Setup the image context using the passed image.
UIGraphicsBeginImageContext(self.size)
//Setups up the font attributes that will be later used to dictate how the text should be drawn
let textFontAttributes = [
NSFontAttributeName: textFont,
NSForegroundColorAttributeName: textColor,
] as [String : Any]
//Put the image into a rectangle as large as the original image.
self.draw(in: CGRect(x:0, y:0, width:self.size.width, height: self.size.height))
// Creating a point within the space that is as bit as the image.
let rect: CGRect = CGRect(x:atPoint.x, y:atPoint.y, width:self.size.width, height:self.size.height)
//Now Draw the text into an image.
drawText.draw(in: rect, withAttributes: textFontAttributes)
// Create a new image out of the images we have created
let newImage: UIImage? = UIGraphicsGetImageFromCurrentImageContext()
// End the context now that we have the image we need
UIGraphicsEndImageContext()
//And pass it back up to the caller.
return newImage
}
}