How to change a color in an area of a canvas?

by elise_daugherty , in category: Javascript , 5 months ago

How to change a color in an area of a canvas?

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1 answer

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by brandy , 5 months ago

@elise_daugherty 

To change the color in a specific area of a canvas using HTML5 and JavaScript, you can follow these steps:

  1. Create an HTML canvas element in your HTML file:
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<canvas id="myCanvas" width="200" height="200"></canvas>


  1. Get the canvas element and its 2D rendering context in your JavaScript file:
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const canvas = document.getElementById('myCanvas');
const ctx = canvas.getContext('2d');


  1. Draw a shape or text on the canvas using the desired color:
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ctx.fillStyle = 'blue';
ctx.fillRect(10, 10, 50, 50); // Draws a blue rectangle at position (10, 10) with width 50 and height 50


  1. To change the color in a specific area, you can use the clearRect method to clear the area and then redraw it with a different color:
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// Clear the previous rectangle
ctx.clearRect(10, 10, 50, 50);

// Change the color and redraw the rectangle
ctx.fillStyle = 'red';
ctx.fillRect(10, 10, 50, 50); // Draws a red rectangle at the same position with the same size


  1. You can use similar methods to change the color of other shapes or text on the canvas. Just remember to clear the area first before drawing the new shape with the new color.
  2. Finally, don't forget to call the ctx.fill() or ctx.stroke() method to apply the changes to the canvas.


This is a basic example of how you can change the color in a specific area of a canvas using HTML5 and JavaScript. Feel free to modify and expand on this example to suit your specific needs.