etch

✍️ Etch

A Simplified, Declarative Implementation Of CustomPaint For Flutter

Features

• Create your CustomPaint widget declaratively.

    EtchCanvas(
        etchElements: [
            EtchCircle.alignment(
                centerAlignment: Offset.zero,
                radius: 50.0,
            ),
        ],
        child: SizedBox(
          width: 100.0,
          height: 100.0,
        ),
    ),

• Use either points or alignments to define points everywhere

    EtchCanvas(
        etchElements: [
            EtchCircle(
              center: Offset(100, 100),
              radius: 50.0,
            ),
            EtchCircle.alignment(
               centerAlignment: Offset.zero,
               radius: 50.0,
               etchStyle: EtchStyle(
                   color: Colors.red,
               ),
           ),
        ],
        child: SizedBox(
          width: 100.0,
          height: 100.0,
        ),
    ),

• Easy support for Paths

    EtchCanvas(
      etchElements: [
        EtchPath(
          etchPathElements: [
            EtchPathMoveTo(point: Offset(0, 0)),
            EtchPathAddPolygon.alignment(
              pointAlignments: [
                Offset(-1, -1),
                Offset(1, -1),
                Offset(1, 1),
              ],
            ),
            EtchPathQuadraticBezierTo.alignment(
              controlPointAlignment: Offset(1, 0.75),
              endPointAlignment: Offset(-1, 1),
            ),
            EtchPathClose(),
          ],
        ),
      ],
      child: SizedBox(
        width: 100.0,
        height: 100.0,
      ),
    ),

• Work with canvas layers easily

    EtchCanvas(
      etchElements: [
        EtchLayer.rotate(
          rotateZ: 1.2,
          etchElements: [
            EtchRect.alignment(
              topLeftAlignment: Offset(-1, -1),
              bottomRightAlignment: Offset(1, 1),
            ),
          ],
        ),
      ],
      child: SizedBox(
        width: 100.0,
        height: 100.0,
      ),
    ),

• Easy animations with TweenAnimationBuilder

Add animations easily using TweenAnimationBuilder or using normal animation controllers without having to pass down progress or other logic.

    TweenAnimationBuilder<double>(
      duration: const Duration(seconds: 1),
      tween: Tween(begin: 0, end: 2 * pi),
      builder: (context, val, _) {
        return EtchCanvas(
          etchElements: [
            EtchLayer.rotate(
              rotateZ: val,
              etchElements: [
                EtchRect.alignment(
                  topLeftAlignment: Offset(-1, -1),
                  bottomRightAlignment: Offset(1, 1),
                ),
              ],
            ),
          ],
          child: const SizedBox(
            width: 100.0,
            height: 100.0,
          ),
        );
      }
    ),

Getting started

• To get started, add an EtchCanvas to your app:

    EtchCanvas(
        etchElements: [],
    ),

Any elements which have the format 'Etch----' can fit into these (EtchParagraph, EtchPath, EtchCircle, etc).

The default constructor arguments usually take in points while the .alignment constructor takes in alignments. For alignments (-1, -1) is the top left while (1, 1) is the bottom right.

    EtchCanvas(
        etchElements: [
            EtchRect.alignment(
              topLeftAlignment: Offset.zero,
              bottomRightAlignment: Offset(1, 1),
            ),
            EtchOval.alignment(
              topLeftAlignment: Offset(-1, -1),
              bottomRightAlignment: Offset(0, 0),
            ),
            EtchArc.alignment(
              topLeftAlignment: Offset(-1, -1),
              bottomRightAlignment: Offset(1, 1),
              startAngle: 0,
              sweepAngle: 2,
            ),
        ],
    ),

• Use EtchStyle to modify paint properties.

    EtchPath(
      etchPathElements: [
        //...
      ],
      etchStyle: EtchStyle(
        style: PaintingStyle.stroke,
      ),
    ),

You can also supply your own Paint object using EtchStyle.raw().

    EtchPath(
      etchPathElements: [
        //...
      ],
      etchStyle: EtchStyle.raw(
        Paint()..color = Colors.black..// add your props,
      ),
    ),

• To add a path to the elements, use EtchPath. Etch path elements have the naming format EtchPath--- (EtchPathAddPolygon, EtchPathAddArc, EtchPathCubicTo, etc)

    EtchCanvas(
        etchElements: [
             EtchPath(
                 etchPathElements: [
                     EtchPathMoveTo(point: Offset(0, 0)),
                     EtchPathLine(point: Offset(110, 0)),
                     EtchPathLine(point: Offset(110, 110)),
                     EtchPathClose(),
                 ],
                 etchStyle: EtchStyle(
                     style: PaintingStyle.stroke,
                 ),
             ),
        ],
    ),

• To add a layer, use the EtchLayer element. This can have numerous EtchElements inside just like the normal EtchCanvas. Layers can have individual transformations without affecting the rest of the canvas - so you can rotate or scale one layer without affecting the others. EtchLayer, like the Transform widget, has multiple inbuilt transformations - but you can pass in your own Matrix4 using the default constructor.

    EtchCanvas(
        etchElements: [
            EtchLayer.rotate(
              rotateX: 1.2,
              etchElements: [
                EtchRect.alignment(
                  topLeftAlignment: Offset(-1, -1),
                  bottomRightAlignment: Offset(1, 1),
                ),
              ],
            ),
            EtchLayer.scale(
              scale: Offset(1, 2),
              etchElements: [
                EtchRect.alignment(
                  topLeftAlignment: Offset(-1, -1),
                  bottomRightAlignment: Offset(1, 1),
                ),
              ],
            ),
            EtchLayer(
              transform: Matrix4.identity(),
              etchElements: [
                EtchRect.alignment(
                  topLeftAlignment: Offset(-1, -1),
                  bottomRightAlignment: Offset(1, 1),
                ),
              ],
            ),
        ],
    ),

Additional information

Note: This package is currently in an experimental stage and full metrics are not yet ascertained. Please feel free to launch issues or PRs if you face something unexpected while using it.