[CM-1267] String size calculation (#79)

* [ISSUE] added method to size String using typography

* [ISSUE] updated according to TV OS

* Modify size(withFont:) and expand unit tests

* Fix failing tvOS tests

---------

Co-authored-by: Mark Pospesel <[email protected]>

Author: SahilSainiYML

Sources/YMatterType/Extensions/Foundation/String+textSize.swift

@@ -0,0 +1,55 @@
+//
+//  String+textSize.swift
+//  YMatterType
+//
+//  Created by Sahil Saini on 27/03/23.
+//  Copyright © 2022 Y Media Labs. All rights reserved.
+//
+
+import UIKit
+
+extension String {
+    /// Calculates the size of the string rendered with the specified typography.
+    /// - Parameters:
+    ///   - typography: the typography to be used to calculate the string size
+    ///   - traitCollection: the trait collection to apply
+    /// - Returns: the size of the string
+    public func size(
+        withTypography typography: Typography,
+        compatibleWith traitCollection: UITraitCollection?
+    ) -> CGSize {
+        let layout = typography.generateLayout(compatibleWith: traitCollection)
+        let valueSize = self.size(withFont: layout.font)
+        return CGSize(
+            width: valueSize.width,
+            height: max(valueSize.height, layout.lineHeight)
+        )
+    }
+
+    /// Calculates the size of the string rendered with the specified font.
+    ///
+    /// The returned size will be rounded up to the nearest pixel in both width and height.
+    /// - Parameters:
+    ///   - font: the font to be used to calculate the string size
+    ///   - traitCollection: the trait collection to apply (used for `displayScale`)
+    /// - Returns: the size of the string
+    public func size(
+        withFont font: UIFont,
+        compatibleWith traitCollection: UITraitCollection? = nil
+    ) -> CGSize {
+        let scale: CGFloat
+        if let displayScale = traitCollection?.displayScale,
+           displayScale != 0.0 {
+            scale = displayScale
+        } else {
+            scale = UIScreen.main.scale
+        }
+        
+        let fontAttributes = [NSAttributedString.Key.font: font]
+        let size = size(withAttributes: fontAttributes)
+        return CGSize(
+            width: ceil(size.width * scale) / scale,
+            height: ceil(size.height * scale) / scale
+        )
+    }
+}

Tests/YMatterTypeTests/Extensions/Foundation/String+textSizeTests.swift

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+//
+//  String+textSizeTests.swift
+//  YMatterTypeTests
+//
+//  Created by Sahil Saini on 27/03/23.
+//
+
+import XCTest
+@testable import YMatterType
+
+final class StringTextSizeTests: XCTestCase {
+    func test_sizeWithFont_deliversRoundedValues() {
+        // Given
+        let scale = getScale()
+        let pointSize = CGFloat(Int.random(in: 10...24))
+        let traits = UITraitCollection(displayScale: scale)
+        let font = UIFont.systemFont(ofSize: pointSize, weight: .regular)
+        let sut = "Hello"
+
+        // When
+        let size = sut.size(withFont: font, compatibleWith: traits)
+
+        // Then
+        XCTAssertGreaterThan(size.width, 0)
+        XCTAssertGreaterThan(size.height, 0)
+        XCTAssertEqual(size.width, ceil(size.width * scale) / scale)
+        XCTAssertEqual(size.height, ceil(size.height * scale) / scale)
+    }
+
+    func test_sizeWithTypography_deliversRoundedValues() throws {
+        // Given
+        let scale = getScale()
+        let traits = UITraitCollection(displayScale: scale)
+        let typography = try XCTUnwrap(getTypographies().randomElement())
+        let sut = "Hello"
+
+        // When
+        let size = sut.size(withTypography: typography, compatibleWith: traits)
+
+        // Then
+        XCTAssertGreaterThan(size.width, 0)
+        XCTAssertGreaterThan(size.height, 0)
+        XCTAssertEqual(size.width, ceil(size.width * scale) / scale)
+        XCTAssertEqual(size.height, ceil(size.height * scale) / scale)
+    }
+
+    func test_sizeWithTypography_deliversLineHeight() {
+        // Given
+        let typography = Typography(
+            fontFamily: Typography.systemFamily,
+            fontWeight: .bold,
+            fontSize: 24,
+            lineHeight: 32,
+            textStyle: .title1
+        )
+        let sut = "testString"
+
+        // When
+        let size = sut.size(withTypography: typography, compatibleWith: .default)
+
+        // Then
+        XCTAssertGreaterThan(size.height, 0)
+        XCTAssertEqual(size.height, typography.lineHeight)
+    }
+
+#if !os(tvOS)
+    func test_sizeWithTypography_deliversScaledSize() throws {
+        // Given
+        let typography = try XCTUnwrap(getTypographies().randomElement())
+        let sut = "testString"
+        let traits = UITraitCollection(preferredContentSizeCategory: .accessibilityMedium)
+
+        // When
+        let size = sut.size(withTypography: typography, compatibleWith: traits)
+
+        // Then
+        XCTAssertGreaterThan(size.height, typography.lineHeight)
+    }
+#endif
+
+    func test_longerStrings_deliverGreaterWidths() {
+        // Given
+        let typography = Typography(
+            fontFamily: Typography.systemFamily,
+            fontWeight: .bold,
+            fontSize: 24,
+            lineHeight: 32,
+            textStyle: .body
+        )
+        let sut1 = "testString1"
+        let sut2 = "testString"
+
+        // When
+        let sutSize1 = sut1.size(withTypography: typography, compatibleWith: .default)
+        let sutSize2 = sut2.size(withTypography: typography, compatibleWith: .default)
+
+        // Then
+        XCTAssertGreaterThan(sutSize1.height, 0)
+        XCTAssertGreaterThan(sutSize2.height, 0)
+        XCTAssertGreaterThan(sutSize1.width, sutSize2.width)
+        XCTAssertEqual(sutSize1.height, sutSize2.height)
+    }
+
+    func test_emptyString_deliversZeroWidth() {
+        // Given
+        let typography = Typography(
+            fontFamily: Typography.systemFamily,
+            fontWeight: .bold,
+            fontSize: 24,
+            lineHeight: 32,
+            textStyle: .caption1
+        )
+        let sut = ""
+
+        // When
+        let sutSize = sut.size(withTypography: typography, compatibleWith: nil)
+
+        // Then
+        XCTAssertGreaterThan(sutSize.height, 0)
+        XCTAssertEqual(sutSize.width, 0)
+    }
+}
+
+extension StringTextSizeTests {
+    func getScale() -> CGFloat {
+        let scale: CGFloat
+#if os(tvOS)
+        scale = UIScreen.main.scale
+#else
+        scale = CGFloat(Int.random(in: 1...3))
+#endif
+        return scale
+    }
+
+    func getTypographies() -> [Typography] {
+        var typographies: [Typography] = [.systemButton, .systemLabel]
+#if !os(tvOS)
+        typographies.append(.system)
+        typographies.append(.smallSystem)
+#endif
+        return typographies
+    }
+}