v137 · canvas · hdr
HDR Gradient Builder
Construct a gradient where stop colors have luminance values above 1.0 — values that only float-16 canvas can represent faithfully. See the gradient on both a float16 and a clamped uint8 canvas, then sample pixels to compare the raw channel values stored in each.
Configure gradient
Stop A
2.50
Stop B
1.50
Sample point
0.30
float16 (HDR)
Float-16 canvas — values > 1.0 preserved
uint8 (SDR clamped)
Uint8 canvas — values clamped to [0, 255]
Pixel samples at selected position
| Canvas type | R | G | B | A | Clamped? |
|---|
Float16 canvas stores each channel as a 16-bit IEEE 754 half-float,
allowing values outside [0, 1] — essential for HDR content. In a typical SDR uint8 canvas,
any channel value above 1.0 is clamped to 255. When you set luminance × 2.5, red channel 0.8
becomes 2.0 — faithfully stored in float16, clipped to 1.0 in uint8.
see also
- Canvas Floating Point Color Types — feature index
- Tonemap Studio — HDR tone mapping controls
- Float16 canvas basics
- ChromeStatus entry
- Canvas spec