pulp::view::View::BackgroundGradient Struct Reference

One background-image layer. More...

#include <view.hpp>

Public Types
enum class	LinearFrom { endpoints , angle , corner }
	Where a linear gradient's endpoints come from. More...
enum class	RepeatUnit { px , line_fraction }
	What linear_repeat is measured in. More...
enum class	RadialSize {   max_side , farthest_corner , farthest_side , closest_corner ,   closest_side , explicit_radii }
	How a radial gradient's radii are sized, per css-images-3. More...

Public Attributes
int	type = 0
std::size_t	css_image_layer_index = 0
float	x0 = 0
float	y0 = 0
float	x1 = 0
float	y1 = 1
float	radius = 0.7071f
float	angle = 0.0f
float	sweep_turns = 1.0f
std::vector< Color >	colors
std::vector< float >	positions
LinearFrom	linear_from = LinearFrom::endpoints
float	linear_angle = 0.0f
	CSS angle in radians, clockwise from "to top".
float	corner_x = 1.0f
	Signs of the named corner for LinearFrom::corner: x is +1 for right, -1 for left; y is +1 for bottom, -1 for top.
float	corner_y = 1.0f
float	linear_repeat = 0.0f
	The band a repeating-linear-gradient tiles; 0 when the gradient does not repeat.
RepeatUnit	linear_repeat_unit = RepeatUnit::px
bool	positions_in_px = false
	True when positions still hold raw px LENGTHS rather than 0..1 parameters, because every stop named one.
RadialSize	radial_size = RadialSize::max_side
bool	radial_circle = false
	A circle has one radius resolved against the box's diagonal-ish metric; an ellipse gets a separate radius per axis.
float	radial_rx = 0.0f
	RadialSize::explicit_radii: radii as fractions of width and height, plus an absolute term.
float	radial_ry = 0.0f
float	radial_rx_px = 0.0f
float	radial_ry_px = 0.0f
canvas::GradientInterpolation	interpolation
	CSS in <space> [<hue> hue].

Detailed Description

One background-image layer.

CSS background-image takes a comma-separated LIST and paints the FIRST entry on top, so a view holds a stack of these rather than a single gradient. The single-gradient setters below replace the whole stack with one layer, which is what every caller that predates layering wants.

Member Enumeration Documentation

LinearFrom

enum class pulp::view::View::BackgroundGradient::LinearFrom

strong

Where a linear gradient's endpoints come from.

endpoints means x0..y1 are already box fractions and need no box (the four to <side> keywords, and every caller of the explicit setter).

Enumerator
endpoints
angle
corner

RadialSize

enum class pulp::view::View::BackgroundGradient::RadialSize

strong

How a radial gradient's radii are sized, per css-images-3.

max_side is not a CSS keyword — it is the pre-existing radius x max(w,h) circle the explicit setter has always meant, kept so those callers are unaffected.

Enumerator
max_side
farthest_corner
farthest_side
closest_corner
closest_side
explicit_radii

RepeatUnit

enum class pulp::view::View::BackgroundGradient::RepeatUnit

strong

What linear_repeat is measured in.

CSS lets the band be a length (... 1px, 7px — 7 CSS px per tile whatever the box) or a fraction of the gradient line (... 0%, 10%), and the line's length is a function of the laid-out box, so the choice cannot be collapsed before paint.

Enumerator
px
line_fraction

Member Data Documentation

angle

float pulp::view::View::BackgroundGradient::angle = 0.0f

colors

std::vector<Color> pulp::view::View::BackgroundGradient::colors

corner_x

float pulp::view::View::BackgroundGradient::corner_x = 1.0f

Signs of the named corner for LinearFrom::corner: x is +1 for right, -1 for left; y is +1 for bottom, -1 for top.

corner_y

float pulp::view::View::BackgroundGradient::corner_y = 1.0f

css_image_layer_index

std::size_t pulp::view::View::BackgroundGradient::css_image_layer_index = 0

interpolation

canvas::GradientInterpolation pulp::view::View::BackgroundGradient::interpolation

CSS in <space> [<hue> hue].

linear_angle

float pulp::view::View::BackgroundGradient::linear_angle = 0.0f

CSS angle in radians, clockwise from "to top".

Valid for LinearFrom::angle.

linear_from

LinearFrom pulp::view::View::BackgroundGradient::linear_from = LinearFrom::endpoints

linear_repeat

float pulp::view::View::BackgroundGradient::linear_repeat = 0.0f

The band a repeating-linear-gradient tiles; 0 when the gradient does not repeat.

positions are rescaled ONTO this band — 0..1 across one tile — exactly as a repeating conic's are onto its sweep, so the painter only has to place the band and let the shader tile it.

linear_repeat_unit

RepeatUnit pulp::view::View::BackgroundGradient::linear_repeat_unit = RepeatUnit::px

positions

std::vector<float> pulp::view::View::BackgroundGradient::positions

positions_in_px

bool pulp::view::View::BackgroundGradient::positions_in_px = false

True when positions still hold raw px LENGTHS rather than 0..1 parameters, because every stop named one.

The divisor is the gradient line (linear) or horizontal radius (radial), each a function of the laid-out box — and of the background-size TILE when the layer is tiled — so the division belongs at paint.

linear-gradient(<colour> 1px, transparent 1px) under background-size: 100% 32px is a scanline every 32px. Read as parameters instead, both stops land at 1.0 — the far end of the ramp — and the layer paints its first colour over the WHOLE box. That is a monotone wash, and it reads as a missing tile rather than as a misread stop, which is why the two halves have to land together.

radial_circle

bool pulp::view::View::BackgroundGradient::radial_circle = false

A circle has one radius resolved against the box's diagonal-ish metric; an ellipse gets a separate radius per axis.

CSS defaults to ellipse unless circle is named or a single length is given.

radial_rx

float pulp::view::View::BackgroundGradient::radial_rx = 0.0f

RadialSize::explicit_radii: radii as fractions of width and height, plus an absolute term.

A % radius fills the fraction slot and a px radius the absolute one, so both spellings — and a calc() that mixes them — resolve through one expression.

radial_rx_px

float pulp::view::View::BackgroundGradient::radial_rx_px = 0.0f

radial_ry

float pulp::view::View::BackgroundGradient::radial_ry = 0.0f

radial_ry_px

float pulp::view::View::BackgroundGradient::radial_ry_px = 0.0f

radial_size

RadialSize pulp::view::View::BackgroundGradient::radial_size = RadialSize::max_side

radius

float pulp::view::View::BackgroundGradient::radius = 0.7071f

sweep_turns

float pulp::view::View::BackgroundGradient::sweep_turns = 1.0f

type

int pulp::view::View::BackgroundGradient::type = 0

x0

float pulp::view::View::BackgroundGradient::x0 = 0

x1

float pulp::view::View::BackgroundGradient::x1 = 0

y0

float pulp::view::View::BackgroundGradient::y0 = 0

y1

float pulp::view::View::BackgroundGradient::y1 = 1

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The documentation for this struct was generated from the following file:

• /home/runner/work/pulp/pulp/core/view/include/pulp/view/view.hpp