🖼️BinaryBitPatternView

🖼

⬆️ 需要： .binary(digits:)

// 2022.02.12 / (no wrap)  apply .fixedSize() to all `Text`s 
//            + (refactor) .bitsView()
//            / (refactor) .nowrapText() + `modify` closure

import SwiftUI

// T: BinaryFloatingPoint & CustomStringConvertible
struct BinaryBitPatternView<T: BinaryFloatingPoint>: View where T: CustomStringConvertible {
    
    // (binary) floating-point number
    let x: T                            // variable
    var optionalName: String? = nil     // optional variable name
    
    // view body
    var body: some View {
        
        let t = type(of: x)
        let sign = x.sign == .plus ? "+" : "-"
        let signBit = x.sign == .plus ? "0" : "1"
        
        // 🌀BinaryInteger + .binary(digits:)
        // integer -> array of bits ([string])
        let exp = x.exponentBitPattern.binary(digits: t.exponentBitCount)
        let significand = x.significandBitPattern.binary(digits: t.significandBitCount)
        
        // container view
        VStack(spacing: 8) {
            
            // title
            HStack(alignment: .firstTextBaseline, spacing: 24) {
                let bits = 1 + t.exponentBitCount + t.significandBitCount
                nowrapText("\(t)") { $0.font(.largeTitle).bold() }
                nowrapText("floating-point representation", .secondary)
                nowrapText("(\(bits)-bit)")
            }
            
            // floating-point representation
            HStack(alignment: .top, spacing: 1) {
                // sign bit
                bitsView([signBit], "\(sign)", .pink)
                // exponent bits
                bitsView(exp, "exponent (\(t.exponentBitCount)-bit)", .blue)
                // significand bits
                bitsView(significand, "significand (\(t.significandBitCount)-bit)", .green)
            }
            
            // calculation
            HStack() {
                
                // variable name (optional view)
                // name = 
                optionalName.map { name in
                    HStack {
                        nowrapText(name, .blue) { $0.bold() }
                        nowrapText("=", .secondary)
                    }
                }
                
                // x = 
                nowrapText(x, .orange)
                nowrapText("=", .secondary)
                
                // (sign) (significand) × (radix)^(exponent)
                nowrapText(sign, .purple)
                nowrapText(x.significand)
                nowrapText("×", .purple)
                nowrapText(t.radix)
                nowrapText(x.exponent)
                    .scaleEffect(0.6, anchor: .leading)
                    .offset(x: -8, y: -10)
            }
            .padding()
            .border(.pink)
            .padding(.top)
        }
        
    }
}

extension BinaryBitPatternView {
    
    /// a little square view for each bit
    func bit(_ b: String, bg: Color = .green, size: CGFloat = 25) -> some View {
        Text("\(b)").font(.system(.caption, design: .monospaced))
            .foregroundColor(.black)
            .frame(width: size, height: size)
            .background(bg)
            .border(.primary, width: 1)
    }
    
    /// bits view
    func bitsView(_ bits: [String], _ subtitle: String, _ color: Color) -> some View {
        VStack {
            HStack(spacing: 1) {
                ForEach(0..<bits.count) { bit(bits[$0], bg: color) }
            }
            Text(subtitle).fixedSize()    // no wrap
        }
    }
    
    /// no-wrap text
    func nowrapText<T: CustomStringConvertible>(
        _     x: T, 
        _ color: Color          = .primary,
        modify : (Text) -> Text = { $0 }        // text modifier
    ) -> some View {
        modify(Text("\(String(describing: x))"))
            .fixedSize().foregroundColor(color)
    }
    
    /// convenience init
    init(_ x: T, name: String? = nil) { self.init(x: x, optionalName: name) }
}

👁️ 預覽

import SwiftUI

struct ContentView: View {
    var body: some View {
        ScrollView(.horizontal) {
            VStack(spacing: 50) {
                BinaryBitPatternView(Float.pi, name: "pi")
                BinaryBitPatternView(Float.pi.ulp, name: "pi.ulp")
                BinaryBitPatternView(Double.greatestFiniteMagnitude, name: ".greatestFiniteMagnitude")
            }
            .scaleEffect(0.7)
        }
    }
}

📘 手冊

• Swift ⟩ String ⟩ String(_:radix:uppercase:) ⭐️ 將整數用二進位、八進位、十六進位表示。

⬆️ 需要

• .binary(digits:)

👥 相關

• custom View for BinaryFloatingPoint numbers.

• uses ForEach to list a string's characters.

• uses a lot of Texts.

❓

問：改名為「FloatingPointView」❓

History

✏️

1. 2022.02.12

1

⬆️ 需要： .binary(digits:)

import SwiftUI

struct BinaryBitPatternView<T: BinaryFloatingPoint>: View {
    let x: T
    var body: some View {
        
        // type of x
        let t = type(of: x)
        let sign = x.sign == .plus ? "+" : "-"
        
        // x -> bits -> string -> array of bits (string)
        let exp = x.exponentBitPattern.binary(digits: t.exponentBitCount)
        let significand = x.significandBitPattern.binary(digits: t.significandBitCount)
        
        VStack(spacing: 8) {
            
            // title
            Text("\(String(describing: t))")
                .font(.largeTitle).bold()
            + Text("    floating-point representation (\(1 + t.exponentBitCount + t.significandBitCount)-bit)")
            
            // floating-point representation
            HStack(alignment: .top, spacing: 1) {
                // sign bit
                VStack {
                    bit(String(x.signBitPattern.first!), bg: .pink)
                    Text("\(sign)")
                }
                
                // exponent bits
                VStack {
                    HStack(spacing: 1) {
                        ForEach(0..<exp.count) {
                            bit(exp[$0], bg: .blue)
                        }
                    }
                    Text("exponent (\(t.exponentBitCount)-bit)")
                }
                // significand bits
                VStack {
                    HStack(spacing: 1) {
                        ForEach(0..<significand.count) {
                            bit(significand[$0])
                        }
                    }
                    Text("significand (\(t.significandBitCount)-bit)")
                }
            }// HStack
            
            // calculation
            HStack(spacing: 0) {
                Text("\(String(describing: x)) = \(sign)\(String(describing: x.significand)) × \(t.radix)").fixedSize()
                Text("\(String(describing: x.exponent))")
                    .fixedSize()
                    .scaleEffect(0.6, anchor: .leading)
                    .offset(y: -10)
            }
            .padding()
            .border(.pink)
            .padding(.top)
        }
        
    }
}

extension BinaryBitPatternView {
    /// a little square for each bit
    func bit(_ b: String, bg: Color = .green, size: CGFloat = 25) -> some View {
        Text("\(b)").font(.system(.caption, design: .monospaced))
            .foregroundColor(.black)
            .frame(width: size, height: size)
            .background(bg)
            .border(.primary, width: 1)
    }
    /// convenience init
    init(_ x: T) { self.init(x: x) }
}