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<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
// Render serveral equivalent ISO 21496-1 gainmap images with various values for
// globalHdrHeadroom.
// The test images used by this test have an SDR representation (at headroom 0)
// with pixel values in sRGB of:
// #C08040, #8040C0, #40C080, #FFFFFF
// They have an HDR representation (at headroom 1) with pixel values in sRGB of
// #40C080, #C08040, #8040C0 color(srgb 0x17F/0xFF, 0x17F/0xFF, 0x17F/0xFF)
// The test images vary in:
// * Some have SDR as the base image (encoded as sRGB) and some have HDR as the
// base image (encoded as Rec2100 PQ or Rec2100 HLG).
// * Some use sRGB as the gain application primaries, others use Rec2020
// The tests that use a Rec2100 PQ or HLG base are allowed a higher amount of
// error because of the brutal quantization error in those spaces.
const tests = [
{
filename:'pq-clli_none-mdcv_none.png',
desc:'No CLLI or MDCV',
max_linear_value:1000/203,
},
{
filename:'pq-clli_100-mdcv_p3_5000.png',
desc:'CLLI 100, MDCV 5000',
max_linear_value:203/203,
},
{
filename:'pq-clli_500-mdcv_none.png',
desc:'CLLI 500',
max_linear_value:500/203,
},
{
filename:'pq-clli_none-mdcv_rec2020_5000.png',
desc:'MDCV 5000',
max_linear_value:5000/203,
},
];
for (const test of tests) {
promise_test(async () => {
filename = test.filename;
const canvas = new OffscreenCanvas(40, 40);
const ctx = canvas.getContext('2d', {colorType:'float16'});
if (ctx.globalHDRHeadroom === undefined) {
return;
}
const pixelLinearValues = [
100/203,
500/203,
1000/203,
5000/203,
];
const globalHDRHeadroomValues = [
0, // log2(1)
1.3045, // log2(500/203)
4.6224, // log2(5000/203)
Infinity,
];
const globalHDRHeadroomLinear = [
203/203,
500/203,
5000/203,
Infinity,
];
// Draw the image at the specified headrooms.
const image = new Image;
image.src = 'resources/' + filename;
await new Promise(resolve => image.onload = resolve);
for (let hdrHeadroomIndex = 0; hdrHeadroomIndex < 4; ++hdrHeadroomIndex) {
ctx.globalHDRHeadroom = globalHDRHeadroomValues[hdrHeadroomIndex];
ctx.drawImage(image, 0, 10*hdrHeadroomIndex);
}
// Read back a pixel in each solid color region.
for (let hdrHeadroomIndex = 0; hdrHeadroomIndex < 4; ++hdrHeadroomIndex) {
for (let pixelIndex = 0; pixelIndex < 4; ++pixelIndex) {
const name = 'globalHDRHeadroom: ' +
globalHDRHeadroomValues[hdrHeadroomIndex] +
', hdrHeadroomIndex:' +
hdrHeadroomIndex;
const data = ctx.getImageData(
5 + 10*pixelIndex, 5 + 10*hdrHeadroomIndex, 1, 1,
{colorSpace:'rec2100-linear', pixelFormat:'rgba-float16'});
if (test.max_linear_value <= globalHDRHeadroomLinear[hdrHeadroomIndex]) {
// If the test image's (max nits)/203 is <= exp2(globalHDRHeadroom),
// then no tone mapping is performed.
if (pixelLinearValues[pixelIndex] <=
globalHDRHeadroomLinear[hdrHeadroomIndex]) {
// Values below the target will be unchanged.
const kEps = 0.15;
assert_approx_equals(
data.data[0], pixelLinearValues[pixelIndex], kEps,
'No tone mapping');
} else {
// Values above the target may be clamped.
const kEps = 0.05;
assert_greater_than(
data.data[0], globalHDRHeadroomLinear[hdrHeadroomIndex] - kEps,
'Tone map to or above target max');
}
} else {
// If the test image doesn't fit in targeted headroom, then tone
// mapping will happen.
if (pixelLinearValues[pixelIndex] == test.max_linear_value) {
// Pixels equal to the content maximum will map to the target
// maximum.
const kEps = 0.05;
assert_approx_equals(
data.data[0], globalHDRHeadroomLinear[hdrHeadroomIndex], kEps,
'Tone map to target max');
} else if (pixelLinearValues[pixelIndex] > test.max_linear_value) {
// Pixels greater than content maximum will map to be greater or
// equal to the target maximum.
const kEps = 0.05;
assert_greater_than(
data.data[0], globalHDRHeadroomLinear[hdrHeadroomIndex] - kEps,
'Tone map to or above target max');
} else {
// Pixels less than the content maximum will map to a value less
// than the target maximum.
const kEps = 0.05;
assert_less_than(
data.data[0], globalHDRHeadroomLinear[hdrHeadroomIndex],
'Tone map below target max');
}
}
}
}
}, test.desc);
}
</script>