Shape Tooltips

HTML5 Canvas Shape Tooltips with Konva

This demo shows how to create tooltips that follow the mouse cursor when hovering over shapes. It demonstrates:

1. Creating custom shapes using the sceneFunc
2. Handling mouse events (mousemove, mouseout)
3. Using multiple layers for better organization
4. Creating dynamic tooltips that follow the cursor

Vanilla

import Konva from 'konva';

const stage = new Konva.Stage({
  container: 'container',
  width: window.innerWidth,
  height: window.innerHeight,
});

const shapesLayer = new Konva.Layer();
const tooltipLayer = new Konva.Layer();

// Create custom triangle shape
const triangle = new Konva.Shape({
  stroke: 'black',
  fill: '#00D2FF',
  strokeWidth: 1,
  sceneFunc: function (context) {
    context.beginPath();
    context.moveTo(120, 50);
    context.lineTo(250, 80);
    context.lineTo(150, 170);
    context.closePath();
    context.fillStrokeShape(this);
  },
});

// Create circle
const circle = new Konva.Circle({
  x: 250,
  y: stage.height() / 2,
  fill: 'red',
  stroke: 'black',
  strokeWidth: 4,
  radius: 70,
});

// Create tooltip
const tooltip = new Konva.Text({
  text: '',
  fontFamily: 'Calibri',
  fontSize: 12,
  padding: 5,
  textFill: 'white',
  fill: 'black',
  alpha: 0.75,
  visible: false,
});

// Add event listeners for triangle
triangle.on('mousemove', () => {
  const mousePos = stage.getPointerPosition();
  tooltip.position({
    x: mousePos.x + 5,
    y: mousePos.y + 5,
  });
  tooltip.text('Cyan Triangle');
  tooltip.show();
});

triangle.on('mouseout', () => {
  tooltip.hide();
});

// Add event listeners for circle
circle.on('mousemove', () => {
  const mousePos = stage.getPointerPosition();
  tooltip.position({
    x: mousePos.x + 5,
    y: mousePos.y + 5,
  });
  tooltip.text('Red Circle');
  tooltip.show();
});

circle.on('mouseout', () => {
  tooltip.hide();
});

// Add shapes and tooltip to layers
shapesLayer.add(triangle);
shapesLayer.add(circle);
tooltipLayer.add(tooltip);

// Add layers to stage
stage.add(shapesLayer);
stage.add(tooltipLayer);

React

import React from 'react';
import { Stage, Layer, Shape, Circle, Text } from 'react-konva';

const CustomShape = ({ onMouseMove, onMouseOut }) => {
  return (
    <Shape
      stroke="black"
      fill="#00D2FF"
      strokeWidth={1}
      sceneFunc={(context, shape) => {
        context.beginPath();
        context.moveTo(120, 50);
        context.lineTo(250, 80);
        context.lineTo(150, 170);
        context.closePath();
        context.fillStrokeShape(shape);
      }}
      onMouseMove={onMouseMove}
      onMouseOut={onMouseOut}
    />
  );
};

const App = () => {
  const [tooltipPos, setTooltipPos] = React.useState({ x: 0, y: 0 });
  const [tooltipText, setTooltipText] = React.useState('');
  const [isTooltipVisible, setTooltipVisible] = React.useState(false);

  const handleMouseMove = (e, text) => {
    const stage = e.target.getStage();
    const pos = stage.getPointerPosition();
    setTooltipPos({
      x: pos.x + 5,
      y: pos.y + 5,
    });
    setTooltipText(text);
    setTooltipVisible(true);
  };

  const handleMouseOut = () => {
    setTooltipVisible(false);
  };

  return (
    <Stage width={window.innerWidth} height={window.innerHeight}>
      <Layer>
        <CustomShape
          onMouseMove={(e) => handleMouseMove(e, 'Cyan Triangle')}
          onMouseOut={handleMouseOut}
        />
        <Circle
          x={250}
          y={window.innerHeight / 2}
          radius={70}
          fill="red"
          stroke="black"
          strokeWidth={4}
          onMouseMove={(e) => handleMouseMove(e, 'Red Circle')}
          onMouseOut={handleMouseOut}
        />
      </Layer>
      <Layer>
        <Text
          x={tooltipPos.x}
          y={tooltipPos.y}
          text={tooltipText}
          fontFamily="Calibri"
          fontSize={12}
          padding={5}
          textFill="white"
          fill="black"
          alpha={0.75}
          visible={isTooltipVisible}
        />
      </Layer>
    </Stage>
  );
};

export default App;

Vue

<template>
  <v-stage :config="stageConfig">
    <v-layer>
      <v-shape
        :config="{
          stroke: 'black',
          fill: '#00D2FF',
          strokeWidth: 1,
          sceneFunc: drawTriangle,
        }"
        @mousemove="(e) => handleMouseMove(e, 'Cyan Triangle')"
        @mouseout="handleMouseOut"
      />
      <v-circle
        :config="{
          x: 250,
          y: stageConfig.height / 2,
          radius: 70,
          fill: 'red',
          stroke: 'black',
          strokeWidth: 4,
        }"
        @mousemove="(e) => handleMouseMove(e, 'Red Circle')"
        @mouseout="handleMouseOut"
      />
    </v-layer>
    <v-layer>
      <v-text
        :config="{
          ...tooltipConfig,
          visible: isTooltipVisible,
        }"
      />
    </v-layer>
  </v-stage>
</template>

<script setup>
import { ref, computed } from 'vue';

const stageConfig = {
  width: window.innerWidth,
  height: window.innerHeight,
};

const tooltipPos = ref({ x: 0, y: 0 });
const tooltipText = ref('');
const isTooltipVisible = ref(false);

const tooltipConfig = computed(() => ({
  x: tooltipPos.value.x,
  y: tooltipPos.value.y,
  text: tooltipText.value,
  fontFamily: 'Calibri',
  fontSize: 12,
  padding: 5,
  textFill: 'white',
  fill: 'black',
  alpha: 0.75,
}));

const drawTriangle = (context, shape) => {
  context.beginPath();
  context.moveTo(120, 50);
  context.lineTo(250, 80);
  context.lineTo(150, 170);
  context.closePath();
  context.fillStrokeShape(shape);
};

const handleMouseMove = (e, text) => {
  const stage = e.target.getStage();
  const pos = stage.getPointerPosition();
  tooltipPos.value = {
    x: pos.x + 5,
    y: pos.y + 5,
  };
  tooltipText.value = text;
  isTooltipVisible.value = true;
};

const handleMouseOut = () => {
  isTooltipVisible.value = false;
};
</script>

Instructions: Move your mouse over the shapes to see tooltips appear. The tooltips will follow your cursor and display information about each shape.