awaforge

pdfColor

AGPL-3.0-onlyRelease 2L4

Applying the colour operators to a graphics state — ISO 32000-2 §8.6.

Module pdfColor | Source packages/front/office/pdf/src/content/color.js | Deps pdfErrors | Worker-safe yes

Mutates gstate.strokeColor / gstate.fillColor for the 12 PDF colour operators: g/G, rg/RG, k/K, cs/CS, sc/SC, scn/SCN. Pattern / Separation / DeviceN spaces accept a trailing /PatternName on scn/SCN — captured as gstate.<slot>.pattern. When scn/SCN carries no trailing name, any previously captured pattern is deleted.

Resolve

const c = runtime.resolve('pdfColor');
// Returns: { applyColorOp }

API

Method Signature Returns
applyColorOp (gstate, { op, args }) => void Mutates the gstate in place.

Operator → mutation

Op Target Effect
g / G fill / stroke { space: 'DeviceGray', components: [n] }
rg / RG fill / stroke { space: 'DeviceRGB', components: [r,g,b] }
k / K fill / stroke { space: 'DeviceCMYK', components: [c,m,y,k] }
cs / CS fill / stroke { space: name, components: device default }
sc / SC fill / stroke replaces components only (numeric args kept, others dropped)
scn / SCN fill / stroke components plus an optional pattern when the last arg is a name

Defaults per named space

Space Default components
DeviceGray [0]
DeviceRGB [0, 0, 0]
DeviceCMYK [0, 0, 0, 1]
any other []

Examples

Set the fill colour in RGB

const c = runtime.resolve('pdfColor');
c.applyColorOp(gstate, {
    op: 'rg',
    args: [{type:'real',value:0.8},{type:'real',value:0.2},{type:'real',value:0.1}]
});
gstate.fillColor;  // { space:'DeviceRGB', components:[0.8,0.2,0.1] }

Set the stroke space

c.applyColorOp(gstate, { op: 'CS', args: [{type:'name',value:'DeviceCMYK'}] });
gstate.strokeColor;  // { space:'DeviceCMYK', components:[0,0,0,1] }

Pattern through scn

c.applyColorOp(gstate, {
    op: 'scn',
    args: [{type:'real',value:0.5}, {type:'name',value:'P1'}]
});
gstate.fillColor.pattern;     // 'P1'
gstate.fillColor.components;  // [0.5]

Errors

Code Class When
pdf/color/unknown-op ContractError applyColorOp called with a non-colour operator.
pdf/color/bad-name ContractError cs/CS without a name argument.
pdf/color/short-args ContractError Fewer numeric arguments than required by g/rg/k and their stroke variants.
pdf/color/bad-num ContractError An argument expected to be numeric has another type.

See also