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2.608kb
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// |
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// ChartContext.swift |
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// USB Meter |
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// |
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// Created by Bogdan Timofte on 14/04/2020. |
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// Copyright © 2020 Bogdan Timofte. All rights reserved. |
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// |
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import CoreGraphics |
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import SwiftUI |
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class ChartContext {
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private var rect : CGRect? |
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private var pad: CGFloat = 0 |
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var isValid: Bool {
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get {
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return rect != nil && rect!.width > 0 && rect!.height > 0 |
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} |
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} |
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var size: CGSize {
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get {
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guard rect != nil else {
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track("Invalid Context")
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fatalError() |
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} |
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return rect!.size |
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} |
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} |
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var origin: CGPoint {
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get {
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guard rect != nil else {
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track("Invalid Context")
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fatalError() |
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} |
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return rect!.origin |
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} |
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} |
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var minValue: Double {
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return rect == nil ? .nan : Double(rect!.minY) |
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} |
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var maxValue: Double {
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get {
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return rect == nil ? .nan : Double(rect!.maxY) |
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} |
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} |
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func reset() {
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rect = nil |
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padding() |
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} |
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func include( point: CGPoint ) {
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if rect == nil {
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rect = CGRect(origin: point, size: .zero) |
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padding() |
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} else {
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rect = rect!.union(CGRect(origin: point, size: .zero)) |
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padding() |
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} |
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} |
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func padding() {
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guard rect != nil else {
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track("Invalid Context")
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pad = 0 |
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fatalError() |
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} |
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pad = rect!.size.height * Constants.chartUnderscan |
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} |
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func yAxisLabel( for itemNo: Int, of items: Int ) -> Double {
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let labelSpace = Double(rect!.height) / Double(items - 1) |
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let labelRelativeValue = labelSpace * Double(itemNo - 1) |
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return minValue + labelRelativeValue |
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} |
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// MARK: Conversii dubioase |
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func xAxisLabel( for itemNo: Int, of items: Int ) -> Double {
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let labelSpace = Double(rect!.width) / Double(items - 1) |
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let labelRelativeValue = labelSpace * Double(itemNo - 1) |
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return Double(rect!.origin.x) + labelRelativeValue |
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} |
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func placeInRect (point: CGPoint) -> CGPoint {
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guard rect != nil else {
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track("Invalid Context")
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fatalError() |
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} |
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guard rect!.width != 0 else {
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fatalError() |
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} |
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guard rect!.height != 0 else {
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fatalError() |
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} |
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let x = (point.x - rect!.origin.x)/rect!.width |
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let y = (pad + point.y - rect!.origin.y)/rect!.height |
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return CGPoint(x: x, y: 1 - y * Constants.chartOverscan) |
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} |
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} |