/**
 * The gradient ramp bound at group 1, shared by the marks that fill from one.
 * The stops are baked into a 1D texture on the CPU, so a gradient costs a
 * sample rather than a stop loop per fragment.
 */
export declare const GRADIENT_BLOCK = "// coords = (x1, y1, x2, y2) in normalized item space,\n// bounds = (x, y, w, h) of the item in canvas coordinates,\n// misc = (kind, r1, r2, unused). kind: 1 = linear, 2 = radial.\nstruct GradientParams {\n  coords: vec4<f32>,\n  bounds: vec4<f32>,\n  misc: vec4<f32>,\n}\n\n@group(1) @binding(0) var stopSampler: sampler;\n@group(1) @binding(1) var stopRamp: texture_2d<f32>;\n@group(1) @binding(2) var<uniform> gradient: GradientParams;\n\n// p is normalized to the item, wh is the item size in pixels. Linear gradients\n// evaluate in normalized space, matching vega's canvas renderer. Radial ones\n// are circular in pixel space with radii scaled by max(w, h).\nfn gradientT(p: vec2<f32>, wh: vec2<f32>) -> f32 {\n    if gradient.misc.x < 1.5 {\n        let a = gradient.coords.xy;\n        let b = gradient.coords.zw;\n        let ab = b - a;\n        let len2 = max(dot(ab, ab), 1e-6);\n        return clamp(dot(p - a, ab) / len2, 0.0, 1.0);\n    }\n    // Radial: the pencil of circles running from (x1, y1, r1) to (x2, y2, r2),\n    // which is what createRadialGradient interpolates. The stop is the largest\n    // t whose circle passes through the point, so it solves\n    // a*t*t - 2*b*t + c = 0 for the circle centre and radius at t. Taking the\n    // distance from the outer centre instead is exact only where the two are\n    // concentric. Canvas draws nothing outside the cone the circles sweep,\n    // which is what a negative discriminant means here.\n    let m = max(wh.x, wh.y);\n    let c1 = gradient.coords.xy * wh;\n    let c2 = gradient.coords.zw * wh;\n    let r1 = gradient.misc.y * m;\n    let r2 = gradient.misc.z * m;\n    let cd = c2 - c1;\n    let dr = r2 - r1;\n    let pd = p * wh - c1;\n    let a = dot(cd, cd) - dr * dr;\n    let b = dot(pd, cd) + r1 * dr;\n    let c = dot(pd, pd) - r1 * r1;\n    if abs(a) < 1e-6 {\n        if abs(b) < 1e-6 {\n            return 1.0;\n        }\n        return clamp(c / (2.0 * b), 0.0, 1.0);\n    }\n    let disc = b * b - a * c;\n    if disc < 0.0 {\n        return 1.0;\n    }\n    let root = sqrt(disc);\n    let hi = (b + root) / a;\n    let lo = (b - root) / a;\n    // the larger t wins, but only where its circle has a radius to draw with\n    if r1 + hi * dr >= 0.0 {\n        return clamp(hi, 0.0, 1.0);\n    }\n    return clamp(lo, 0.0, 1.0);\n}\n\n// The ramp's colour at a point in canvas coordinates, spread over the bounds.\nfn rampAt(world: vec2<f32>) -> vec4<f32> {\n    let p = (world - gradient.bounds.xy) / max(gradient.bounds.zw, vec2<f32>(1e-6, 1e-6));\n    return textureSample(stopRamp, stopSampler, vec2<f32>(gradientT(p, gradient.bounds.zw), 0.5));\n}";