问题
I want to render some text on one of my screens that has a 3dish look to it. I am using UIKit and standard views controllers etc.
The effect will look something like this:
Can this be done somehow with UIKit & iOS? Ordinarily I would just use a static png however, the text is dynamic and updates based on user data
回答1:
The following code might not be perfect, but it should be a good starting point.
Basically you draw the font twice, slightly changing the size and the offset. Depending on the font and size you're dealing with you're probably have to play a bit with fontSize, fontSizeDelta and fontOffset.
The result looks somewhat like this:
- (UIImage *)imageWith3dString:(NSString *)text
{
CGFloat fontSize = 150.0;
CGFloat fontSizeDelta = 3.0;
CGFloat fontOffset = 5.0;
NSString *fontName = @"Bebas";
UIFont *font = [UIFont fontWithName:fontName size:fontSize];
CGSize textSize = [text sizeWithFont:font
constrainedToSize:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX)];
CGSize size = CGSizeMake(textSize.width, fontSize);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef ctx = CGBitmapContextCreate(NULL,
(int)size.width,
(int)size.height,
8,
(int)(4 * size.width),
colorSpace,
kCGImageAlphaPremultipliedLast);
// Draw with shadow
CGContextSetShadowWithColor(ctx, CGSizeMake(0, 0), 10.0, [UIColor colorWithWhite:0.0 alpha:0.6].CGColor);
CGContextSetRGBStrokeColor(ctx, 1.0, 1.0, 1.0, 0.6);
CGContextSetAllowsAntialiasing(ctx, YES);
CGContextSetLineWidth(ctx, 2.0);
CGContextSetTextDrawingMode(ctx, kCGTextFillStroke);
CGContextSetRGBFillColor(ctx, 222 / 255.0, 222 / 255.0, 222 / 255.0, 1.0);
CGContextSetCharacterSpacing(ctx, 2.6);
CGContextSelectFont(ctx, [fontName UTF8String], fontSize - fontSizeDelta, kCGEncodingMacRoman);
CGContextShowTextAtPoint(ctx, 0.0, 3.0 + fontOffset, [text UTF8String], text.length);
CGContextSetShadowWithColor(ctx, CGSizeZero, 0.0, NULL); // disable shadow
CGContextSetCharacterSpacing(ctx, 1.0);
CGContextSelectFont(ctx, [fontName UTF8String], fontSize, kCGEncodingMacRoman);
CGContextShowTextAtPoint(ctx, 0.0, 3.0, [text UTF8String], text.length);
CGImageRef imageRef = CGBitmapContextCreateImage(ctx);
UIImage *image = [UIImage imageWithCGImage:imageRef];
CGColorSpaceRelease(colorSpace);
CGImageRelease(imageRef);
CGContextRelease(ctx);
return image;
}
- (void)viewDidLoad
{
[super viewDidLoad];
UIImageView *imageView = [[UIImageView alloc] initWithImage:[self imageWith3dString:@"3"]];
[self.view addSubview:imageView];
}
YMMV
回答2:
Well, here is a basic sample of this.
The idea is you draw layers of the same text over and over with an x/y 1 offset to create the "depth" look.
I have create an UIImage Category, called UIImage+3d, which you can test:
This is the header (.h) file
//
// UIImage+3D.h
//
// Created by Lefteris Haritou on 12/10/12.
// Feel Free to use this code, but please keep the credits
//
#import <UIKit/UIKit.h>
@interface UIImage (Extensions)
+ (UIImage *)create3DImageWithText:(NSString *)_text Font:(UIFont*)_font ForegroundColor:(UIColor*)_foregroundColor ShadowColor:(UIColor*)_shadowColor outlineColor:(UIColor*)_outlineColor depth:(int)_depth useShine:(BOOL)_shine;
@end
Here is the implementation (.m) file
//
// UIImage+3D.m
//
// Created by Lefteris Haritou on 12/10/12.
// Feel Free to use this code, but please keep the credits
//
#import "UIImage+3D.h"
#import <CoreText/CoreText.h>
#import <QuartzCore/QuartzCore.h>
@implementation UIImage (Extensions)
+ (UIImage *)create3DImageWithText:(NSString *)_text Font:(UIFont*)_font ForegroundColor:(UIColor*)_foregroundColor ShadowColor:(UIColor*)_shadowColor outlineColor:(UIColor*)_outlineColor depth:(int)_depth useShine:(BOOL)_shine {
//calculate the size we will need for our text
CGSize expectedSize = [_text sizeWithFont:_font constrainedToSize:CGSizeMake(MAXFLOAT, MAXFLOAT)];
//increase our size, as we will draw in 3d, so we need extra space for 3d depth + shadow with blur
expectedSize.height+=_depth+5;
expectedSize.width+=_depth+5;
UIColor *_newColor;
UIGraphicsBeginImageContextWithOptions(expectedSize, NO, [[UIScreen mainScreen] scale]);
CGContextRef context = UIGraphicsGetCurrentContext();
//because we want to do a 3d depth effect, we are going to slightly decrease the color as we move back
//so here we are going to create a color array that we will use with required depth levels
NSMutableArray *_colorsArray = [[NSMutableArray alloc] initWithCapacity:_depth];
CGFloat *components = (CGFloat *)CGColorGetComponents(_foregroundColor.CGColor);
//add as a first color in our array the original color
[_colorsArray insertObject:_foregroundColor atIndex:0];
//create a gradient of our color (darkening in the depth)
int _colorStepSize = floor(100/_depth);
for (int i=0; i<_depth; i++) {
for (int k=0; k<3; k++) {
if (components[k]>(_colorStepSize/255.f)) {
components[k]-=(_colorStepSize/255.f);
}
}
_newColor = [UIColor colorWithRed:components[0] green:components[1] blue:components[2] alpha:CGColorGetAlpha(_foregroundColor.CGColor)];
//we are inserting always at first index as we want this array of colors to be reversed (darkest color being the last)
[_colorsArray insertObject:_newColor atIndex:0];
}
//we will draw repeated copies of our text, with the outline color and foreground color, starting from the deepest
for (int i=0; i<_depth; i++) {
//change color
_newColor = (UIColor*)[_colorsArray objectAtIndex:i];
//draw the text
CGContextSaveGState(context);
CGContextSetShouldAntialias(context, YES);
//draw outline if this is the last layer (front one)
if (i+1==_depth) {
CGContextSetLineWidth(context, 1);
CGContextSetLineJoin(context, kCGLineJoinRound);
CGContextSetTextDrawingMode(context, kCGTextStroke);
[_outlineColor set];
[_text drawAtPoint:CGPointMake(i, i) withFont:_font];
}
//draw filling
[_newColor set];
CGContextSetTextDrawingMode(context, kCGTextFill);
//if this is the last layer (first one we draw), add the drop shadow too and the outline
if (i==0) {
CGContextSetShadowWithColor(context, CGSizeMake(-2, -2), 4.0f, _shadowColor.CGColor);
}
else if (i+1!=_depth){
//add glow like blur
CGContextSetShadowWithColor(context, CGSizeMake(-1, -1), 3.0f, _newColor.CGColor);
}
[_text drawAtPoint:CGPointMake(i, i) withFont:_font];
CGContextRestoreGState(context);
}
//if we need to apply the shine
if (_shine) {
//create an alpha mask from the top most layer of the image, so we can add a shine effect over it
CGColorSpaceRef genericRGBColorspace = CGColorSpaceCreateDeviceRGB();
CGContextRef imageContext = CGBitmapContextCreate(NULL, (int)expectedSize.width, (int)expectedSize.height, 8, (int)expectedSize.width * 4, genericRGBColorspace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
UIGraphicsPushContext(imageContext);
CGContextSetTextDrawingMode(imageContext, kCGTextFill);
[_text drawAtPoint:CGPointMake(_depth-1, _depth-1) withFont:_font];
CGImageRef alphaMask = CGBitmapContextCreateImage(imageContext);
CGContextRelease(imageContext);
UIGraphicsPopContext();
//draw shine effect
//clip context to the mask we created
CGRect drawRect = CGRectZero;
drawRect.size = expectedSize;
CGContextSaveGState(context);
CGContextClipToMask(context, drawRect, alphaMask);
CGContextSetBlendMode(context, kCGBlendModeLuminosity);
size_t num_locations = 4;
CGFloat locations[4] = { 0.0, 0.4, 0.6, 1};
CGFloat gradientComponents[16] = {
0.0, 0.0, 0.0, 1.0,
0.6, 0.6, 0.6, 1.0,
0.8, 0.8, 0.8, 1.0,
0.0, 0.0, 0.0, 1.0
};
CGGradientRef glossGradient = CGGradientCreateWithColorComponents(genericRGBColorspace, gradientComponents, locations, num_locations);
CGPoint start = CGPointMake(0, 0);
CGPoint end = CGPointMake(0, expectedSize.height);
CGContextDrawLinearGradient(context, glossGradient, start, end, 0);
CGColorSpaceRelease(genericRGBColorspace);
CGGradientRelease(glossGradient);
CGImageRelease(alphaMask);
CGContextRestoreGState(context);
}
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return finalImage;
}
@end
And to use this , simply import the category extension then use it as follows:
UIImage *my3dImage = [UIImage create3DImageWithText:@"3" Font:[UIFont systemFontOfSize:250] ForegroundColor:[UIColor colorWithRed:(200/255.f) green:(200/255.f) blue:(200/255.f) alpha:1.0] ShadowColor:[UIColor blackColor] outlineColor:[UIColor colorWithRed:(225/255.f) green:(225/255.f) blue:(225/255.f) alpha:1.0] depth:8 useShine:NO];
UIImageView *imgView = [[UIImageView alloc] initWithImage:my3dImage];
[self.view addSubview: imgView];
Another example is this:
UIImage *my3dImage = [UIImage create3DImageWithText:@"3D" Font:[UIFont fontWithName:@"MarkerFelt-Wide" size:180] ForegroundColor:[UIColor colorWithRed:(222/255.f) green:(100/255.f) blue:(100/255.f) alpha:1.0] ShadowColor:[UIColor blackColor] outlineColor:[UIColor colorWithRed:(216/255.f) green:(120/255.f) blue:(120/255.f) alpha:1.0] depth:6 useShine:NO];
UIImageView *imgView = [[UIImageView alloc] initWithImage:my3dImage];
imgView.center = self.view.center;
[self.view addSubview: imgView];
And the result looks like this:
I edited the code to add a shine effect over the image, which I believe makes it look cooler
UIImage *my3dImage = [UIImage create3DImageWithText:@"3D" Font:[UIFont fontWithName:@"MarkerFelt-Wide" size:180] ForegroundColor:[UIColor colorWithRed:(222/255.f) green:(100/255.f) blue:(100/255.f) alpha:1.0] ShadowColor:[UIColor blackColor] outlineColor:[UIColor colorWithRed:(216/255.f) green:(120/255.f) blue:(120/255.f) alpha:1.0] depth:6 useShine:YES];
UIImageView *imgView = [[UIImageView alloc] initWithImage:my3dImage];
imgView.center = self.view.center;
[self.view addSubview: imgView];
来源：https://stackoverflow.com/questions/13766268/3d-text-effect-in-ios