How to implement minimap of kineticjs layer?

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by lew , in category: Javascript , 4 months ago

How to implement minimap of kineticjs layer?

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1 answer

Member

by dedrick , 4 months ago

@lew 

To implement a minimap of a KineticJS layer, you can follow these steps:

  1. Create a new KineticJS layer for the minimap:
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var minimapLayer = new Kinetic.Layer();


  1. Create a rectangle representing the minimap view area:
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var minimapRect = new Kinetic.Rect({
    x: 0,
    y: 0,
    width: stage.getWidth() / 4, // adjust size as needed
    height: stage.getHeight() / 4,
    fill: 'rgba(0, 0, 0, 0.2)',
    stroke: 'black',
    strokeWidth: 1
});

minimapLayer.add(minimapRect);


  1. Add the minimap layer to the stage:
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stage.add(minimapLayer);


  1. Update the minimap view area based on the user's viewport position:
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// Update minimap view area based on main layer's position and scale
minimapRect.setX(mainLayer.getX() * scale);
minimapRect.setY(mainLayer.getY() * scale);
minimapRect.setWidth(stage.getWidth() / scale);
minimapRect.setHeight(stage.getHeight() / scale);


  1. Adjust the scale of the minimap view area based on the user's viewport scale:
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// Update scale of minimap view area based on main layer's scale
var scale = mainLayer.getScale().x; // assuming x and y scales are the same
minimapLayer.setScale({x: 1 / scale, y: 1 / scale });


  1. Hook up event listeners to update the minimap view area based on user interactions (e.g. panning and zooming the main layer).


By following these steps, you should be able to implement a minimap of a KineticJS layer that shows a scaled-down view of the main layer, allowing users to navigate large canvases more easily.