MondrianLayout

A way to build AutoLayout rapidly than using InterfaceBuilder(XIB, Storyboard) in iOS.

Describing the layout ergonomically in the code

🏗 Structured Layout API

Mondrian.buildSubviews(on: view) {
  VStackBlock {
  
    titleLabel
    
    HStackBlock {
      cancelButton
      sendButton
    }      
  }
  .padding(24)
}

---

💃 To preserve flexibility of AutoLayout, we have classical style API

Classical Layout API

sendButton.mondrian.layout
  .width(120)
  .top(.toSuperview)
  .trailing(.toSuperview)
  .leading(.to(cancelButton).trailing)
  .activate()

---

Support the project

<a href="https://www.buymeacoffee.com/muukii"> <img width="545" alt="yellow-button" src="https://user-images.githubusercontent.com/1888355/146226808-eb2e9ee0-c6bd-44a2-a330-3bbc8a6244cf.png"> </a>

🤵🏻‍♂️💭 We guess we still don't cover the all of use-cases. Please feel free to ask what you've faced case in Issues!

<img width="246" alt="CleanShot 2021-06-17 at 21 12 03@2x" src="https://user-images.githubusercontent.com/1888355/122394225-b1da4e80-cfb0-11eb-9e62-f5627c817b66.png">

This image laid out by MondrianLayout

<details><summary>Layout code</summary> <p>

HStackBlock(spacing: 2, alignment: .fill) {
  VStackBlock(spacing: 2, alignment: .fill) {
    UIView.mock(
      backgroundColor: .mondrianRed,
      preferredSize: .init(width: 28, height: 28)
    )

    UIView.mock(
      backgroundColor: .layeringColor,
      preferredSize: .init(width: 28, height: 50)
    )

    UIView.mock(
      backgroundColor: .mondrianYellow,
      preferredSize: .init(width: 28, height: 28)
    )

    UIView.mock(
      backgroundColor: .layeringColor,
      preferredSize: .init(width: 28, height: 28)
    )

    HStackBlock(alignment: .fill) {
      UIView.mock(
        backgroundColor: .layeringColor,
        preferredSize: .init(width: 28, height: 28)
      )
      UIView.mock(
        backgroundColor: .layeringColor,
        preferredSize: .init(width: 28, height: 28)
      )
    }
  }

  VStackBlock(spacing: 2, alignment: .fill) {
    HStackBlock(spacing: 2, alignment: .fill) {
      UIView.mock(
        backgroundColor: .layeringColor,
        preferredSize: .init(width: 28, height: 28)
      )
      VStackBlock(spacing: 2, alignment: .fill) {
        HStackBlock(spacing: 2, alignment: .fill) {
          UIView.mock(
            backgroundColor: .mondrianYellow,
            preferredSize: .init(width: 28, height: 28)
          )
          UIView.mock(
            backgroundColor: .layeringColor,
            preferredSize: .init(width: 28, height: 28)
          )
        }
        UIView.mock(
          backgroundColor: .layeringColor,
          preferredSize: .init(width: 28, height: 28)
        )
      }
    }

    HStackBlock(spacing: 2, alignment: .fill) {
      VStackBlock(spacing: 2, alignment: .fill) {
        UIView.mock(
          backgroundColor: .layeringColor,
          preferredSize: .init(width: 28, height: 28)
        )
        UIView.mock(
          backgroundColor: .mondrianBlue,
          preferredSize: .init(width: 28, height: 28)
        )
      }

      UIView.mock(
        backgroundColor: .layeringColor,
        preferredSize: .init(width: 28, height: 28)
      )

      VStackBlock(spacing: 2, alignment: .fill) {
        UIView.mock(
          backgroundColor: .layeringColor,
          preferredSize: .init(width: 28, height: 28)
        )
        UIView.mock(
          backgroundColor: .layeringColor,
          preferredSize: .init(width: 28, height: 28)
        )
      }
    }

    HStackBlock(spacing: 2, alignment: .fill) {
      UIView.mock(
        backgroundColor: .mondrianRed,
        preferredSize: .init(width: 28, height: 28)
      )
      VStackBlock(spacing: 2, alignment: .fill) {
        UIView.mock(
          backgroundColor: .layeringColor,
          preferredSize: .init(width: 28, height: 28)
        )
        UIView.mock(
          backgroundColor: .layeringColor,
          preferredSize: .init(width: 28, height: 28)
        )
      }
    }

  }

}
.overlay(
  UILabel.mockMultiline(text: "Mondrian Layout", textColor: .white)
    .viewBlock
    .padding(4)
    .background(
      UIView.mock(
        backgroundColor: .layeringColor
      )
      .viewBlock
    )
    .relative(bottom: 8, right: 8)
)

</p> </details>

Structured layout API and Classical layout API

• 🌟 Ergonomically Enables us to describe layout by DSL (like SwiftUI's layout).
• 🌟 Automatic adding subviews according to layout representation.
• 🌟 Supports integeration with system AutoLayout API.
• 🌟 Provides classical layout API that describing constraints each view.

Introduction

A DSL based layout builder with AutoLayout

AutoLayout is super powerful to describe the layout and how it changes according to the bounding box.
What if we get a more ergonomic interface to declare the constraints.

Structured layout API

| | | |---|---| |<img width="364" src="https://user-images.githubusercontent.com/1888355/122650919-75555100-d170-11eb-8edf-834497dec211.png" />|<img width="364" alt="CleanShot 2021-06-17 at 21 13 11@2x" src="https://user-images.githubusercontent.com/1888355/122394356-d9311b80-cfb0-11eb-8c8c-f5117593ffbe.png">|

<img width="649" alt="CleanShot 2021-06-17 at 21 14 10@2x" src="https://user-images.githubusercontent.com/1888355/122394462-f9f97100-cfb0-11eb-9838-91f22c148bd9.png">

Unstructured layout API (classic style)

<img width="330" alt="classic@2x" src="https://user-images.githubusercontent.com/1888355/124358722-84ea9480-dc5c-11eb-95f7-e0250779b65c.png">

Future direction

• Optimize the code - still verbose implementation because we're not sure if the API can be stable.
• Brushing up the DSL - to be stable in describing.
• Adding more modifiers for fine tuning in layout.
• Tuning up the stack block's behavior.
• Adding a way to setting constraints independently besides DSL
  • AutoLayout is definitely powerful to describe the layout. We might need to set the constraints additionally since DSL can't describe every pattern of the layout.

Demo app

You can see many layout examples from the demo application.

https://user-images.githubusercontent.com/1888355/122651186-142e7d00-d172-11eb-8bde-f4432d0a0ac9.mp4

Overview

MondrianLayout enables us to describe layouts of subviews by DSL (powered by resultBuilders)
It's like describing in SwiftUI, but this behavior differs a bit since laying out by AutoLayout system.

To describe layout, use buildSubviews as entrypoint.
This method creates a set of NSLayoutConstraint, UILayoutGuide, and modifiers of UIView.
Finally, those apply. You don't need to call addSubview. that goes automatically according to hierarchy from layout descriptions.

class MyView: UIView {

  let nameLabel: UILabel
  let detailLabel: UILabel

  init() {
    super.init(frame: .zero)
    
    // Seting up constraints constraints, layoutGuides and adding subviews
    Mondrian.buildSubviews(on: self) {
      VStackBlock {
        nameLabel
        detailLabel
      }
    }
    
    // Seting up constraints for the view itself.
    Mondrian.layout {
      self.mondrian.layout.width(200) // can be method cain.
    }
    
  }
}

Examples

Sample code assumes run in UIView. (self is UIView)
You can replace it with UIViewController.view.

Layout subviews inside safe-area

Attaching to top and bottom safe-area.

Mondrian.buildSubviews(on: self) {
  LayoutContainer(attachedSafeAreaEdges: .vertical) {
    VStackBlock {
      ...
    }
  }
}

or

Mondrian.buildSubviews(on: self) {
  VStackBlock {
    ...
  }
  .container(respectingSafeAreaEdges: .vertical)
}

Put a view snapping to edge

Mondrian.buildSubviews(on: self) {
  ZStackBlock {
    backgroundView.viewBlock.relative(0)    
  }
}

synonyms:

ZStackBlock(alignment: .attach(.all)) {
  backgroundView
}

ZStackBlock {
  backgroundView.viewBlock.alignSelf(.attach(.all))
}

Add constraints to view itself - using classic layout

Mondrian.layout {
  self.mondrian.layout.width(...).height(...)
}

or

self.mondrian.layout.width(...).height(...).activate()

Stacking views on Z axis

relative(0) fills to the edges of ZStackBlock.

Mondrian.buildSubviews(on: self) {
  ZStackBlock {
    profileImageView.viewBlock.relative(0)
    textOverlayView.viewBlock.relative(0)
  }
}

Centering a label with minimum padding

ZStackBlock {
  myLabel
    .relative(.all, .min(20))
}

ZStackBlock {
  ZStackBlock {
    myLabel
  }
  .padding(20) /// a minimum padding for the label in the container
}

Detail

Vertically and Horizontally Stack layout

VStackBlock

Alignment | center(default) | leading | trailing | fill | |---|---|---|---| |<img width="155" alt="CleanShot 2021-06-17 at 00 06 10@2x" src="https://user-images.githubusercontent.com/1888355/122244438-d75b4f80-ceff-11eb-90ea-8982758ed0b0.png">|<img width="151" alt="CleanShot 2021-06-17 at 00 05 19@2x" src="https://user-images.githubusercontent.com/1888355/122244276-b7c42700-ceff-11eb-90d0-492c3fbc5076.png">|<img width="159" alt="CleanShot 2021-06-17 at 00 05 33@2x" src="https://user-images.githubusercontent.com/1888355/122244312-c01c6200-ceff-11eb-888d-0a37b63f666a.png">|<img width="159" alt="CleanShot 2021-06-17 at 00 05 42@2x" src="https://user-images.githubusercontent.com/1888355/122244341-c6124300-ceff-11eb-9da8-dcbb4425909a.png">|

HStackBlock

| center(default) | top | bottom | fill | |---|---|---|---| |<img width="358" alt="CleanShot 2021-06-17 at 00 09 43@2x" src="https://user-images.githubusercontent.com/1888355/122245037-5486c480-cf00-11eb-872a-e98cfce7262e.png">|<img width="359" alt="CleanShot 2021-06-17 at 00 09 51@2x" src="https://user-images.githubusercontent.com/1888355/122245054-58b2e200-cf00-11eb-9691-607a