"Arrange the sequence of drawImage() calls and ensure they are preserved when rendering onto the canvas

Question

"Arrange the sequence of drawImage() calls and ensure they are preserved when rendering onto the canvas

My page has a total of 6 canvas elements. Users can upload images using the <input type="file"> button, and each image should be displayed within one of the canvas elements, arranged from left to right in sequential order.

However, I am having difficulty getting the images to display properly from left to right on the canvases.

For example, if the first image is uploaded, it should appear in "can1". Subsequent images should go to "can2", "can3", and so on. If an image is deleted from "can2", the image in "can3" should move to take its place.

javascript jquery css html

Answer 1

Answer №1

To keep things simple, one method is to save all the images in an array and whenever a new image is added or removed, refresh each canvas by redrawing them.

var images = [],
    contexts = [ // array containing the drawing contexts of the canvases ];
function refreshCanvases() {
    for (var i = 0, len = contexts.length; i < len; i++) {
        var context = contexts[i],
            image = images[i];
        // If width/height are defined elsewhere
        context.clearRect(0, 0, width, height);
        if (image) {
            context.drawImage(image, x, y, width, height);
        }
    }
}

function addImage() {
    // Code to load the image...
    images.push(image);
    refreshCanvases();
}

Repeat this process for adding and removing images as needed.

Answer 2

To keep things simple, one method is to save all the images in an array and whenever a new image is added or removed, refresh each canvas by redrawing them.

var images = [],
    contexts = [ // array containing the drawing contexts of the canvases ];
function refreshCanvases() {
    for (var i = 0, len = contexts.length; i < len; i++) {
        var context = contexts[i],
            image = images[i];
        // If width/height are defined elsewhere
        context.clearRect(0, 0, width, height);
        if (image) {
            context.drawImage(image, x, y, width, height);
        }
    }
}

function addImage() {
    // Code to load the image...
    images.push(image);
    refreshCanvases();
}

Repeat this process for adding and removing images as needed.

"Arrange the sequence of drawImage() calls and ensure they are preserved when rendering onto the canvas

Answer №1

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