test_toDataURL_parameters.html

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<title>Canvas test: toDataURL parameters (Bug 564388)</title>

<script src="/tests/SimpleTest/SimpleTest.js"></script>

<link rel="stylesheet" href="/tests/SimpleTest/test.css">

<body>

<p>

This test covers the JPEG and webp quality parameter. If (when) the HTML5 spec changes the

allowed parameters for ToDataURL, new tests should go here.

</p>

<canvas id="c" width="100" height="100"><p class="fallback">FAIL (fallback content)</p></canvas>

<script>

let canvas = document.getElementById('c');

let ctx = canvas.getContext("2d");

ctx.strokeStyle = '#FF0000';

ctx.fillStyle = '#00FF00';

ctx.fillRect(0, 0, 100, 100);

ctx.beginPath();

ctx.moveTo(10, 10);

ctx.lineTo(90, 90);

ctx.stroke();

let pngData = canvas.toDataURL('image/png');

let pngQuality = canvas.toDataURL('image/png', 0.1);

is(pngQuality, pngData, "Quality is not supported for PNG images");

function checkType(imagetype) {

    let imageTypeString = 'image/' + imagetype;

    let imageTypeUpperString = 'IMAGE/' + imagetype.toUpperCase();

    let data = canvas.toDataURL(imageTypeString);

    if (data.match(new RegExp('^data:image\/' + imagetype + '[;,]'))) {

        // Test the JPEG/wepb quality parameter

        let fullQuality = canvas.toDataURL(imageTypeString, 1.0);

        let lowQuality = canvas.toDataURL(imageTypeString, 0.1);

        isnot(lowQuality, fullQuality, "A low quality (0.1) should differ from high quality (1.0) " + imageTypeString);

        let medQuality = canvas.toDataURL(imageTypeString, 0.5);

        isnot(medQuality, fullQuality, "A medium quality (0.5) should differ from high (1.0) " + imageTypeString);

        isnot(medQuality, lowQuality, "A medium quality (0.5) should differ from low (0.5) " + imageTypeString);

        let tooHigh = canvas.toDataURL(imageTypeString, 2.0);

        is(tooHigh, data, "Quality above 1.0 is treated as unspecified " + imageTypeString);

        let tooLow = canvas.toDataURL(imageTypeString, -1.0);

        is(tooLow, data, "Quality below 0.0 is treated as unspecified " + imageTypeString);

        let lowQualityExtra = canvas.toDataURL(imageTypeString, 0.1, 'foo', 'bar', null);

        is(lowQualityExtra, lowQuality, "Quality applies even if extra arguments are present " + imageTypeString);

        let lowQualityUppercase = canvas.toDataURL(imageTypeUpperString, 0.1);

        is(lowQualityUppercase, lowQuality, "Quality applies to " + imageTypeString + " regardless of case");

        let lowQualityString = canvas.toDataURL(imageTypeString, '0.1');

        isnot(lowQualityString, lowQuality, "Quality must be a number (should not be a string) " + imageTypeString);

    } else {

        ok(false, "should get a data url " + imageTypeString);

checkType('jpeg');

checkType('webp');

</script>