Is HTML5 canvas and image on polygon possible?

Yes, it is possible to draw images on polygons in HTML5 canvas. You can achieve this by creating a pattern from an image and applying it as a fill, or by using transformation matrices to manipulate how the image is drawn within the polygon shape.

Method 1: Using Image Patterns

Create a pattern using the image object and set it as the fillStyle for your polygon:

<canvas id="myCanvas" width="400" height="300"></canvas>

<script>
const canvas = document.getElementById('myCanvas');
const context = canvas.getContext("2d");

// Create an image object
const img = new Image();
img.onload = function() {
    // Create pattern from image
    const pattern = context.createPattern(img, "repeat");
    context.fillStyle = pattern;
    
    // Draw a triangle polygon
    context.beginPath();
    context.moveTo(100, 50);
    context.lineTo(200, 50);
    context.lineTo(150, 150);
    context.closePath();
    context.fill();
};
img.src = '/html5/images/pattern.png';
</script>

Method 2: Using Transformation Matrix

For more control over image positioning and scaling within arbitrary polygons, use transformation matrices:

<canvas id="transformCanvas" width="400" height="300"></canvas>

<script>
const canvas2 = document.getElementById('transformCanvas');
const ctx = canvas2.getContext("2d");

const image = new Image();
image.onload = function() {
    // Save current state
    ctx.save();
    
    // Create clipping path (pentagon)
    ctx.beginPath();
    ctx.moveTo(200, 50);
    ctx.lineTo(250, 100);
    ctx.lineTo(230, 170);
    ctx.lineTo(170, 170);
    ctx.lineTo(150, 100);
    ctx.closePath();
    ctx.clip();
    
    // Transform and draw image
    ctx.setTransform(1.5, 0.2, 0.1, 1.2, 150, 50);
    ctx.drawImage(image, 0, 0);
    
    // Restore original state
    ctx.restore();
};
image.src = '/html5/images/sample.jpg';
</script>

Key Points

• Pattern Method: Best for repeating textures across the polygon surface
• Transform Method: Provides precise control over image placement and distortion
• Clipping: Use clip() to ensure the image stays within polygon boundaries
• Always use save() and restore() when applying transformations

Comparison

Conclusion

Both pattern creation and transformation matrices enable image rendering within polygons in HTML5 canvas. Choose patterns for texture effects and transformations for precise image manipulation within polygon shapes.