feat(drawText): add support for text alignment (left, right)

guhungry · Oct 23, 2024 · 91c4072 · 91c4072
1 parent 15c0344
commit 91c4072
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Showing 3 changed files with 37 additions and 7 deletions.
diff --git a/Sources/WCPhotoManipulator/Models/TextStyle.swift b/Sources/WCPhotoManipulator/Models/TextStyle.swift
@@ -14,6 +14,8 @@ import UIKit
     let color: UIColor
     /// The font of the text.
     let font: UIFont
+    /// The alignment of the text. Default value is left.
+    public var alignment: NSTextAlignment = .left
     /// The thickness of the text. Default value is 0.
     let thickness: CGFloat
     /// The rotation angle of the text in degrees. Default value is 0.
@@ -135,6 +137,7 @@ import UIKit
         TextStyle:
           color: \(color)
           font: \(font)
+          alignment: \(alignment)
           thickness: \(thickness)
           rotation: \(rotation)
           shadowRadius: \(shadowRadius)

diff --git a/Sources/WCPhotoManipulator/UIImage+PhotoManipulator.swift b/Sources/WCPhotoManipulator/UIImage+PhotoManipulator.swift
@@ -46,15 +46,12 @@ public extension UIImage {
 
     // Text
     @objc func drawText(_ text: String, position: CGPoint, style: TextStyle, scale: CGFloat) -> UIImage? {
-        UIGraphicsBeginImageContextWithOptions(self.size, false, scale)
-        if let context = UIGraphicsGetCurrentContext() {
-            context.translateBy(x: position.x, y: position.y)
-            context.rotate (by: -style.rotation * CGFloat.pi / 180.0) //45˚
-            context.translateBy(x: -position.x, y: -position.y)
-        }
+        let paragraphStyle = NSMutableParagraphStyle.init()
+        paragraphStyle.alignment = style.alignment
         var textStyles: [NSAttributedString.Key: Any] = [
             .font: style.font,
             .foregroundColor: style.color,
+            .paragraphStyle: paragraphStyle
         ]
         if (style.thickness > 0) {
             textStyles[.strokeColor] = style.color;
@@ -63,8 +60,21 @@ public extension UIImage {
         if (style.shadowRadius > 0 && style.shadowColor != nil) {
             textStyles[.shadow] = style.shadow;
         }
+        let textSize = (text as NSString).size(withAttributes: textStyles)
+
+        var adjustedPosition = position
+        if (style.alignment == .right) {
+            adjustedPosition = CGPoint(x: position.x - textSize.width, y: position.y)
+        }
+
+        UIGraphicsBeginImageContextWithOptions(self.size, false, scale)
+        if let context = UIGraphicsGetCurrentContext() {
+            context.translateBy(x: position.x, y: position.y)
+            context.rotate (by: -style.rotation * CGFloat.pi / 180.0) //45˚
+            context.translateBy(x: -position.x, y: -position.y)
+        }
 
-        (text as NSString).draw(at: position, withAttributes: textStyles)
+        (text as NSString).draw(in: CGRect(origin: adjustedPosition, size: textSize), withAttributes: textStyles)
 
         let rotatedImageWithText = UIGraphicsGetImageFromCurrentImageContext();
         UIGraphicsEndImageContext()

diff --git a/Tests/WCPhotoManipulatorTests/UIImage+PhotoManipulatorSwiftTests.swift b/Tests/WCPhotoManipulatorTests/UIImage+PhotoManipulatorSwiftTests.swift
@@ -136,6 +136,23 @@ class UIImage_PhotoManipulatorSwiftTests: XCTestCase {
         XCTAssertNotNil(image)
         XCTAssertEqual(image.size, CGSize(width: 800, height: 530))
     }
+
+    func testDrawText_WhenAlignRight_ShouldReturnCorrectly() throws {
+        image = UIImage.init(namedTest: "background.jpg")
+        XCTAssertNotNil(image)
+
+        let style = TextStyle(color: .blue, size: 42, thickness: 5, rotation: -30)
+        style.alignment = .right
+        image = image.drawText("Test Text To Align Right Draw", position: CGPoint(x: 400, y: 60), style: style, scale: 2)
+        image = image.drawText("Right", position: CGPoint(x: 400, y: 100), style: style, scale: 2)
+        image = image.drawText("Right Multiple\nLine", position: CGPoint(x: 400, y: 140), style: style, scale: 2)
+        style.alignment = .left
+        image = image.drawText("Test Text To Align Left Draw", position: CGPoint(x: 400, y: 60), style: style, scale: 2)
+        image = image.drawText("Left", position: CGPoint(x: 400, y: 100), style: style, scale: 2)
+        image = image.drawText("Left Multiple\nLine", position: CGPoint(x: 400, y: 140), style: style, scale: 2)
+        XCTAssertNotNil(image)
+        XCTAssertEqual(image.size, CGSize(width: 800, height: 530))
+    }
 
     // Overlay Image
     func testOverlayImage_WhenNoScale_ShouldReturnCorrectly() throws {