PencilCup 1.0.0

You want to add pod 'PencilCup', '~> 1.0' similar to the following to your Podfile:

target 'MyApp' do
  pod 'PencilCup', '~> 1.0'
end

Then run a pod install inside your terminal, or from CocoaPods.app.

Alternatively to give it a test run, run the command:

pod try PencilCup

PencilCup 1.0.0

By
Jo Albright
joalbright

Tools built to help use CoreGraphics more Swiftly

Usage

To run the example project, clone the repo, and run pod install from the Example directory first.

Add these Code Snippets into Xcode to help with using the new operators.

Code Snippet Directory : ~/Library/Developer/Xcode/UserData/CodeSnippets/

Motivation

Core Graphics is an amazingly useful library that I work with in every app I build. But I also have spent a lot of time writing lines of code to draw things that are very simple.

Main Problems

each point on a path uses a new line of code
you must pass "context" with every CGContext function
CGContext options set using functions instead of methods

let context = UIGraphicsGetCurrentContext()
UIColor(white: 0.9, alpha: 1).set()
CGContextFillRect(context, rect)
UIColor(white: 0.2, alpha: 1).set()

CGContextSetLineCap(context, .Round)
CGContextSetLineJoin(context, .Round)
CGContextSetLineWidth(context, 1)
CGContextTranslateCTM(context, (rect.width - 188) / 2, (rect.height - 300) / 2)

CGContextMoveToPoint(context,126.01,89.44)
CGContextAddCurveToPoint(context,116.37, 89.19, 105.65, 89.06, 94.35, 89.06)
CGContextAddCurveToPoint(context, 52.35, 89.06, 18.3, 90.8, 18.3, 94.24)
CGContextAddCurveToPoint(context, 18.3, 97.68, 52.35, 101.51, 94.35, 101.51)
CGContextAddCurveToPoint(context, 104.7, 101.51, 114.57, 101.28, 123.57, 100.87)
CGContextAddLineToPoint(context,126.01,89.44)
CGContextFillPath(context)

CGContextMoveToPoint(context,140, 99.75)
CGContextAddLineToPoint(context, 150.28, 49.72)
CGContextAddCurveToPoint(context, 150.5, 48.64, 151.56, 47.94, 152.64, 48.17)
CGContextAddLineToPoint(context, 162.37, 50.18)
CGContextAddCurveToPoint(context, 163.46, 50.4, 164.15, 51.46, 163.93, 52.54)
CGContextAddLineToPoint(context, 154.43, 98.52)
CGContextStrokePath(context)

22 lines of code

New Patterns

You now have the ability to set context options using extension methods. Infix operators open up the ability to build a multi point path on a single line of code.

New Features

typealiases PCPoint, PCSize, PCScale, PCDelta
CGRect extended with inset methods and global initializer functions
CGContextRef extended with methods that simplify setup
infix operators for points and paths

Operator Pattern

let (bgColor,cupColor) = (UIColor(white: 0.9, alpha: 1).CGColor, UIColor(white: 0.2, alpha: 1).CGColor)

let context = UIGraphicsGetCurrentContext()?.round()?.color(bgColor)?.rect(rect)?.fill()
context?.color(cupColor)?.round()?.line(1)?.offset((rect.width - 188) / 2, (rect.height - 300) / 2)

context ->- (126.01,89.44) -~- (116.37,89.19,105.65,89.06,94.35,89.06) -~- (52.35,89.06,18.3,90.8,18.3,94.24)
context -~- (18.3,97.68,52.35,101.51,94.35,101.51) -~- (104.7,101.51,114.57,101.28,123.57,100.87) -+- (126.01,89.44) -■ nil

context ->- (140,99.75) -+- (150.28,49.72) -~- (150.5,48.64,151.56,47.94,152.64,48.17) -+- (162.37,50.18)
context -~- (163.46,50.4,164.15,51.46,163.93,52.54) -+- (154.43,98.52) -□ nil

7 lines of code

Function Pattern

let (bgColor,cupColor) = (UIColor(white: 0.9, alpha: 1).CGColor, UIColor(white: 0.2, alpha: 1).CGColor)

let context = UIGraphicsGetCurrentContext()?.round()?.color(bgColor)?.rect(rect)?.fill()
context?.color(cupColor)?.round()?.line(1)?.offset((rect.width - 188) / 2, (rect.height - 300) / 2)

context?.m(126.01,89.44)?.c(116.37,89.19,105.65,89.06,94.35,89.06)?.c(52.35,89.06,18.3,90.8,18.3,94.24)
context?.c(18.3,97.68,52.35,101.51,94.35,101.51)?.c(104.7,101.51,114.57,101.28,123.57,100.87)?.l(126.01,89.44)?.fill()

context?.m(140,99.75)?.l(150.28,49.72)?.c(150.5,48.64,151.56,47.94,152.64,48.17)?.l(162.37,50.18)
context?.c(163.46,50.4,164.15,51.46,163.93,52.54)?.l(154.43,98.52)?.stroke()

7 lines of code

I personally enjoy the operator pattern, because the visuals of the operators make it more readable for me. But both are great patterns.

Screens

CoreGraphics Drawn PencilCup Logo
ColorWheel and ColorBar Classes in Example Project
- gradient steps are changlable
- bars have values to change hue, saturation, brightness, alpha

Installation

PencilCup is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "PencilCup"

PencilCup is also available through Swift Package Manager. Please take a look at the link to learn more about how to use SwiftPM.

import PackageDescription

let package = Package(
    name: "YOUR_PACKAGE_NAME",
    dependencies: [
        .Package(url: "https://github.com/joalbright/PencilCup.git", majorVersion: 0)
    ]
)

Author

Jo Albright

License

PencilCup is available under the MIT license. See the LICENSE file for more info.