87 lines
2.6 KiB
Swift
87 lines
2.6 KiB
Swift
//
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// Copyright 2019 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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//
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import SignalServiceKit
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class ImageEditorStrokeItem: ImageEditorItem {
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enum StrokeType: Equatable {
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case pen
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case highlighter
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case blur
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}
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// Until we need to serialize these items,
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// just use UIColor.
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let color: UIColor?
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let strokeType: StrokeType
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typealias StrokeSample = ImageEditorSample
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let unitSamples: [StrokeSample]
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// Expressed as a "Unit" value as a fraction of
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// min(width, height) of the destination viewport.
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let unitStrokeWidth: CGFloat
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func strokeWidth(forDstSize dstSize: CGSize) -> CGFloat {
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ImageEditorStrokeItem.strokeWidth(forUnitStrokeWidth: unitStrokeWidth, dstSize: dstSize)
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}
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init(color: UIColor? = nil,
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strokeType: StrokeType,
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unitSamples: [StrokeSample],
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unitStrokeWidth: CGFloat) {
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self.color = color
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self.strokeType = strokeType
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self.unitSamples = unitSamples
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self.unitStrokeWidth = unitStrokeWidth
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super.init(itemType: .stroke)
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}
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init(itemId: String,
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color: UIColor? = nil,
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strokeType: StrokeType,
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unitSamples: [StrokeSample],
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unitStrokeWidth: CGFloat) {
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self.color = color
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self.strokeType = strokeType
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self.unitSamples = unitSamples
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self.unitStrokeWidth = unitStrokeWidth
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super.init(itemId: itemId, itemType: .stroke)
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}
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// First value is default unitStrokeWidth for a given stroke type.
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// Second value is the power to raise adjustment factor (slider value) if the factor is greater than 1.
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private class func metrics(forStrokeType strokeType: StrokeType) -> (CGFloat, CGFloat) {
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switch strokeType {
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case .pen:
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return (0.02, 3)
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case .highlighter:
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return (0.04, 3)
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case .blur:
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return (0.05, 2)
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}
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}
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class func unitStrokeWidth(forStrokeType strokeType: StrokeType,
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widthAdjustmentFactor adjustmentFactor: CGFloat) -> CGFloat {
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let (defaultWidth, power) = metrics(forStrokeType: strokeType)
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let multiplier: CGFloat
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if adjustmentFactor > 1 {
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multiplier = pow(adjustmentFactor, power)
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} else {
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multiplier = adjustmentFactor
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}
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return defaultWidth * multiplier
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}
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class func strokeWidth(forUnitStrokeWidth unitStrokeWidth: CGFloat, dstSize: CGSize) -> CGFloat {
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return CGFloat.clamp01(unitStrokeWidth) * min(dstSize.width, dstSize.height)
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}
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}
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