brush.c File Reference

#include "iop/drawlayer/brush.h"
#include "iop/drawlayer/cache.h"
#include "iop/drawlayer/paint.h"
#include "iop/drawlayer/brush_profile.h"
#include "common/darktable.h"
#include "develop/noise_generator.h"
#include <math.h>
#include <string.h>

Include dependency graph for iop/drawlayer/brush.c:

Data Structures
struct	dt_drawlayer_sprinkle_preview_t
struct	dt_drawlayer_brush_runtime_view_t
struct	dt_drawlayer_brush_pixel_eval_t

Typedefs
typedef struct dt_drawlayer_sprinkle_preview_t	dt_drawlayer_sprinkle_preview_t
typedef struct dt_drawlayer_brush_runtime_view_t	dt_drawlayer_brush_runtime_view_t
typedef struct dt_drawlayer_brush_pixel_eval_t	dt_drawlayer_brush_pixel_eval_t

Functions
static float	_clamp01 (const float v)
	Clamp scalar to [0,1].
static float	_lerpf (const float a, const float b, const float t)
	Linear interpolation helper.
static float	_cell_hash01_from_seed (const uint64_t cell_seed, const uint64_t salt)
	Stable scalar hash in [0,1] from precomputed cell seed.
static float	_cellular_grain_2d (const uint64_t seed, const float x, const float y)
	Grain-like round cellular field. Peaks at grain centers, falls off radially.
static void	_sprinkle_octave_weights (const float coarseness, float *w0, float *w1, float *w2)
	Resolve octave weights from coarseness control.
static float	_sprinkle_noise_at_pixel_precomputed (const float px, const float py, const float scale, const float strength, const float w0, const float w1, const float w2, const uint64_t seed0, const uint64_t seed1, const uint64_t seed2)
	Evaluate sprinkle modulation from precomputed dab constants.
static void	_prepare_sprinkle_preview (const dt_drawlayer_brush_dab_t *dab, const float center_x, const float center_y, const float radius, dt_drawlayer_sprinkle_preview_t *preview)
static float	_sample_sprinkle_preview (const dt_drawlayer_sprinkle_preview_t *preview, const float px, const float py)
static gboolean	_brush_runtime_view_from_state (const dt_drawlayer_paint_stroke_t *stroke, const dt_drawlayer_brush_dab_t *dab, const int origin_x, const int origin_y, const float scale, dt_drawlayer_brush_runtime_view_t *view)
	Build immutable per-dab raster view from stroke runtime state.
static float	_sample_alpha_noise_raw (const dt_drawlayer_brush_dab_t *dab, const dt_drawlayer_brush_runtime_view_t *view, const int pixel_x, const int pixel_y)
	Resolve multiplicative alpha noise at one pixel.
static float	_estimate_alpha_noise_gain (const dt_drawlayer_brush_dab_t *dab, const dt_drawlayer_brush_runtime_view_t *view)
	Estimate per-dab texture gain so noise preserves average opacity across samples.
static float	_stroke_flow_alpha (const dt_drawlayer_brush_dab_t *dab, const float opacity, const float flow, const float sample_opacity_scale, const float profile, const float brush_alpha, const float old_alpha, const float stroke_old_alpha, const gboolean have_stroke_alpha)
	Compute per-pixel source alpha from opacity/flow model.
static gboolean	_prepare_analytic_pixel_context (const dt_drawlayer_brush_runtime_view_t *view, const float sample_opacity_scale, float *stroke_mask, const int stroke_mask_width, const int stroke_mask_height, const int x, const int y, const float old_alpha, dt_drawlayer_brush_pixel_eval_t *pixel_eval)
	Compute full analytic per-pixel brush context.
static gboolean	_prepare_blur_context (dt_aligned_pixel_simd_t *blur_px, const float *buffer, const int width, const dt_drawlayer_brush_runtime_view_t *view)
	Build blur gather color for current dab footprint.
static float	_smudge_hash_signed (const int x, const int y, const int lane)
	Stable signed pseudo-random helper in [-1,1].
static	__attribute__ ((always_inline))
	Bilinear RGBA sample from float buffer.
static float	_smudge_deposit_alpha (const float src_alpha, const float carried_alpha, const float opacity)
	Resolve effective smudge deposit alpha for one pixel.
static dt_aligned_pixel_simd_t	_apply_smudge_stroke_mode (float *buffer, const int width, const int height, dt_drawlayer_paint_stroke_t *runtime_private, const dt_drawlayer_brush_runtime_view_t *view, const float scale, const int origin_x, const int origin_y, const int x, const int y, const float src_alpha, const dt_aligned_pixel_simd_t old_px)
	Apply smudge mode for one pixel and update carried sample.
gboolean	dt_drawlayer_brush_rasterize (dt_drawlayer_cache_patch_t *patch, const float scale, const dt_drawlayer_brush_dab_t *dab, const float sample_opacity_scale, dt_drawlayer_cache_patch_t *stroke_mask, dt_drawlayer_paint_stroke_t *runtime_private)
	Public dab rasterization entry point.
gboolean	dt_drawlayer_brush_rasterize_dab_argb8 (const dt_drawlayer_brush_dab_t *dab, uint8_t *argb, const int width, const int height, const int stride, const float center_x, const float center_y, const float opacity_multiplier)
	Render one dab to 8-bit ARGB surface for GUI cursor preview.
gboolean	dt_drawlayer_brush_rasterize_dab_rgbaf (const dt_drawlayer_brush_dab_t *dab, float *rgba, const int width, const int height, const float center_x, const float center_y, const float opacity_multiplier, const float background_rgb[3])
	Rasterize a single dab preview in linear float RGBA over an opaque background.

Typedef Documentation

dt_drawlayer_brush_pixel_eval_t

typedef struct dt_drawlayer_brush_pixel_eval_t dt_drawlayer_brush_pixel_eval_t

dt_drawlayer_brush_runtime_view_t

typedef struct dt_drawlayer_brush_runtime_view_t dt_drawlayer_brush_runtime_view_t

dt_drawlayer_sprinkle_preview_t

typedef struct dt_drawlayer_sprinkle_preview_t dt_drawlayer_sprinkle_preview_t

Function Documentation

__attribute__()

static __attribute__ ( (always_inline)  )

inlinestatic

Bilinear RGBA sample from float buffer.

Multi-tap smudge source sample with directional jitter.

Note

Coordinates are clamped to valid image bounds.

Parameters

motion_dx	Motion X used to orient anisotropic taps.
motion_dy	Motion Y used to orient anisotropic taps.

References dt_simd_set1(), fx, height, MIN, width, and x.

_apply_smudge_stroke_mode()

static dt_aligned_pixel_simd_t _apply_smudge_stroke_mode ( float *  buffer, const int  width, const int  height, dt_drawlayer_paint_stroke_t *  runtime_private, const dt_drawlayer_brush_runtime_view_t *  view, const float  scale, const int  origin_x, const int  origin_y, const int  x, const int  y, const float  src_alpha, const dt_aligned_pixel_simd_t  old_px  )

static

Apply smudge mode for one pixel and update carried sample.

Precondition

Smudge buffer must be allocated for current dab footprint.

References _clamp01(), _smudge_deposit_alpha(), dt_drawlayer_paint_runtime_get_smudge_pickup(), dt_drawlayer_paint_runtime_have_smudge_pickup(), dt_drawlayer_paint_runtime_smudge_pixels(), dt_drawlayer_paint_runtime_smudge_width(), dt_simd_set1(), dt_store_simd(), height, dt_drawlayer_brush_dab_t::opacity, view(), width, and x.

Referenced by dt_drawlayer_brush_rasterize().

_brush_runtime_view_from_state()

static gboolean _brush_runtime_view_from_state ( const dt_drawlayer_paint_stroke_t *  stroke, const dt_drawlayer_brush_dab_t *  dab, const int  origin_x, const int  origin_y, const float  scale, dt_drawlayer_brush_runtime_view_t *  view  )

static

Build immutable per-dab raster view from stroke runtime state.

Returns

TRUE when dab bounds are valid and non-empty.

References _clamp01(), _sprinkle_octave_weights(), dt_drawlayer_paint_stroke_t::bounds, dt_drawlayer_brush_dab_t::dir_x, dt_drawlayer_brush_dab_t::dir_y, DT_DRAWLAYER_BRUSH_MODE_ERASE, DT_DRAWLAYER_BRUSH_MODE_PAINT, FALSE, dt_drawlayer_brush_dab_t::mode, dt_drawlayer_damaged_rect_t::nw, dt_drawlayer_brush_dab_t::radius, dt_drawlayer_damaged_rect_t::se, dt_drawlayer_brush_dab_t::sprinkle_coarseness, dt_drawlayer_brush_dab_t::sprinkle_size, dt_drawlayer_brush_dab_t::sprinkles, dt_drawlayer_brush_dab_t::stroke_batch, TRUE, dt_drawlayer_damaged_rect_t::valid, view(), dt_drawlayer_brush_dab_t::x, and dt_drawlayer_brush_dab_t::y.

Referenced by dt_drawlayer_brush_rasterize().

_cell_hash01_from_seed()

static float _cell_hash01_from_seed ( const uint64_t  cell_seed, const uint64_t  salt  )

inlinestatic

Stable scalar hash in [0,1] from precomputed cell seed.

References splitmix32().

Referenced by _cellular_grain_2d().

_cellular_grain_2d()

static float _cellular_grain_2d ( const uint64_t  seed, const float  x, const float  y  )

inlinestatic

Grain-like round cellular field. Peaks at grain centers, falls off radially.

References _cell_hash01_from_seed(), _clamp01(), and x.

Referenced by _sprinkle_noise_at_pixel_precomputed().

_clamp01()

static float _clamp01 ( const float  v )

inlinestatic

Clamp scalar to [0,1].

References v.

Referenced by _apply_smudge_stroke_mode(), _brush_runtime_view_from_state(), _cellular_grain_2d(), _prepare_analytic_pixel_context(), _prepare_sprinkle_preview(), _smudge_deposit_alpha(), _sprinkle_octave_weights(), _stroke_flow_alpha(), dt_drawlayer_brush_rasterize(), dt_drawlayer_brush_rasterize_dab_argb8(), and dt_drawlayer_brush_rasterize_dab_rgbaf().

_estimate_alpha_noise_gain()

static float _estimate_alpha_noise_gain ( const dt_drawlayer_brush_dab_t *  dab, const dt_drawlayer_brush_runtime_view_t *  view  )

inlinestatic

Estimate per-dab texture gain so noise preserves average opacity across samples.

References _sample_alpha_noise_raw(), and view().

Referenced by dt_drawlayer_brush_rasterize().

_lerpf()

static float _lerpf ( const float  a, const float  b, const float  t  )

inlinestatic

Linear interpolation helper.

References a, b, and t.

Referenced by _sprinkle_octave_weights(), and _stroke_flow_alpha().

_prepare_analytic_pixel_context()

static gboolean _prepare_analytic_pixel_context ( const dt_drawlayer_brush_runtime_view_t *  view, const float  sample_opacity_scale, float *  stroke_mask, const int  stroke_mask_width, const int  stroke_mask_height, const int  x, const int  y, const float  old_alpha, dt_drawlayer_brush_pixel_eval_t *  pixel_eval  )

static

Compute full analytic per-pixel brush context.

Returns

TRUE when pixel contributes non-zero alpha.

References _clamp01(), _sample_alpha_noise_raw(), _stroke_flow_alpha(), dt_drawlayer_brush_pixel_eval_t::brush_alpha, dt_drawlayer_brush_profile_eval(), FALSE, dt_drawlayer_brush_dab_t::flow, dt_drawlayer_brush_dab_t::opacity, dt_drawlayer_brush_pixel_eval_t::profile, dt_drawlayer_brush_pixel_eval_t::src_alpha, dt_drawlayer_brush_pixel_eval_t::stroke_alpha, dt_drawlayer_brush_pixel_eval_t::stroke_old_alpha, view(), and x.

Referenced by dt_drawlayer_brush_rasterize().

_prepare_blur_context()

static gboolean _prepare_blur_context ( dt_aligned_pixel_simd_t *  blur_px, const float *  buffer, const int  width, const dt_drawlayer_brush_runtime_view_t *  view  )

static

Build blur gather color for current dab footprint.

Returns

TRUE when footprint contributed at least one weighted sample.

References dt_drawlayer_brush_profile_eval(), dt_simd_set1(), FALSE, TRUE, view(), width, and x.

Referenced by dt_drawlayer_brush_rasterize().

_prepare_sprinkle_preview()

static void _prepare_sprinkle_preview ( const dt_drawlayer_brush_dab_t *  dab, const float  center_x, const float  center_y, const float  radius, dt_drawlayer_sprinkle_preview_t *  preview  )

inlinestatic

References _clamp01(), _sprinkle_noise_at_pixel_precomputed(), _sprinkle_octave_weights(), dt_drawlayer_sprinkle_preview_t::enabled, FALSE, dt_drawlayer_sprinkle_preview_t::gain, dt_drawlayer_sprinkle_preview_t::scale, dt_drawlayer_sprinkle_preview_t::seed0, dt_drawlayer_sprinkle_preview_t::seed1, dt_drawlayer_sprinkle_preview_t::seed2, dt_drawlayer_brush_dab_t::sprinkle_coarseness, dt_drawlayer_brush_dab_t::sprinkle_size, dt_drawlayer_brush_dab_t::sprinkles, dt_drawlayer_sprinkle_preview_t::strength, dt_drawlayer_brush_dab_t::stroke_batch, TRUE, dt_drawlayer_sprinkle_preview_t::w0, dt_drawlayer_sprinkle_preview_t::w1, and dt_drawlayer_sprinkle_preview_t::w2.

Referenced by dt_drawlayer_brush_rasterize_dab_argb8(), and dt_drawlayer_brush_rasterize_dab_rgbaf().

_sample_alpha_noise_raw()

static float _sample_alpha_noise_raw ( const dt_drawlayer_brush_dab_t *  dab, const dt_drawlayer_brush_runtime_view_t *  view, const int  pixel_x, const int  pixel_y  )

inlinestatic

Resolve multiplicative alpha noise at one pixel.

Returns

Texture factor.

References _sprinkle_noise_at_pixel_precomputed(), and view().

Referenced by _estimate_alpha_noise_gain(), and _prepare_analytic_pixel_context().

_sample_sprinkle_preview()

static float _sample_sprinkle_preview ( const dt_drawlayer_sprinkle_preview_t *  preview, const float  px, const float  py  )

inlinestatic

References _sprinkle_noise_at_pixel_precomputed(), dt_drawlayer_sprinkle_preview_t::enabled, dt_drawlayer_sprinkle_preview_t::gain, dt_drawlayer_sprinkle_preview_t::scale, dt_drawlayer_sprinkle_preview_t::seed0, dt_drawlayer_sprinkle_preview_t::seed1, dt_drawlayer_sprinkle_preview_t::seed2, dt_drawlayer_sprinkle_preview_t::strength, dt_drawlayer_sprinkle_preview_t::w0, dt_drawlayer_sprinkle_preview_t::w1, and dt_drawlayer_sprinkle_preview_t::w2.

Referenced by dt_drawlayer_brush_rasterize_dab_argb8(), and dt_drawlayer_brush_rasterize_dab_rgbaf().

_smudge_deposit_alpha()

static float _smudge_deposit_alpha ( const float  src_alpha, const float  carried_alpha, const float  opacity  )

inlinestatic

Resolve effective smudge deposit alpha for one pixel.

References _clamp01().

Referenced by _apply_smudge_stroke_mode().

_smudge_hash_signed()

static float _smudge_hash_signed ( const int  x, const int  y, const int  lane  )

inlinestatic

Stable signed pseudo-random helper in [-1,1].

References h, and x.

_sprinkle_noise_at_pixel_precomputed()

static float _sprinkle_noise_at_pixel_precomputed ( const float  px, const float  py, const float  scale, const float  strength, const float  w0, const float  w1, const float  w2, const uint64_t  seed0, const uint64_t  seed1, const uint64_t  seed2  )

inlinestatic

Evaluate sprinkle modulation from precomputed dab constants.

References _cellular_grain_2d(), strength(), w1, w2, and x.

Referenced by _prepare_sprinkle_preview(), _sample_alpha_noise_raw(), and _sample_sprinkle_preview().

_sprinkle_octave_weights()

static void _sprinkle_octave_weights ( const float  coarseness, float *  w0, float *  w1, float *  w2  )

inlinestatic

Resolve octave weights from coarseness control.

References _clamp01(), _lerpf(), c, t, w1, and w2.

Referenced by _brush_runtime_view_from_state(), and _prepare_sprinkle_preview().

_stroke_flow_alpha()

static float _stroke_flow_alpha ( const dt_drawlayer_brush_dab_t *  dab, const float  opacity, const float  flow, const float  sample_opacity_scale, const float  profile, const float  brush_alpha, const float  old_alpha, const float  stroke_old_alpha, const gboolean  have_stroke_alpha  )

inlinestatic

Compute per-pixel source alpha from opacity/flow model.

Assumptions:

• flow uses internal brush convention (see caller conversion),
• sample_opacity_scale already reflects spacing normalization.

References _clamp01(), _lerpf(), DT_DRAWLAYER_BRUSH_MODE_BLUR, DT_DRAWLAYER_BRUSH_MODE_ERASE, DT_DRAWLAYER_BRUSH_MODE_SMUDGE, dt_drawlayer_brush_dab_t::mode, and void().

Referenced by _prepare_analytic_pixel_context().

dt_drawlayer_brush_rasterize()

gboolean dt_drawlayer_brush_rasterize	(	dt_drawlayer_cache_patch_t *	patch,
		const float	scale,
		const dt_drawlayer_brush_dab_t *	dab,
		const float	sample_opacity_scale,
		dt_drawlayer_cache_patch_t *	stroke_mask,
		dt_drawlayer_paint_stroke_t *	runtime_private
	)

Public dab rasterization entry point.

Rasterize one dab into a float RGBA buffer.

Assumes caller already converted coordinates to layer space.

References _apply_smudge_stroke_mode(), _brush_runtime_view_from_state(), _clamp01(), _estimate_alpha_noise_gain(), _prepare_analytic_pixel_context(), _prepare_blur_context(), dt_drawlayer_brush_runtime_view_t::alpha_noise_gain, dt_drawlayer_paint_stroke_t::bounds, DT_DRAWLAYER_BRUSH_MODE_BLUR, DT_DRAWLAYER_BRUSH_MODE_ERASE, DT_DRAWLAYER_BRUSH_MODE_PAINT, DT_DRAWLAYER_BRUSH_MODE_SMUDGE, dt_drawlayer_paint_runtime_ensure_smudge_pixels(), dt_drawlayer_paint_runtime_prepare_dab_context(), dt_simd_set1(), dt_store_simd(), FALSE, dt_drawlayer_brush_dab_t::flow, height, dt_drawlayer_cache_patch_t::height, dt_drawlayer_brush_dab_t::opacity, dt_drawlayer_cache_patch_t::pixels, dt_drawlayer_brush_dab_t::radius, dt_drawlayer_damaged_rect_t::se, dt_drawlayer_brush_pixel_eval_t::src_alpha, dt_drawlayer_brush_pixel_eval_t::stroke_alpha, dt_drawlayer_brush_pixel_eval_t::stroke_old_alpha, TRUE, view(), width, dt_drawlayer_cache_patch_t::width, x, dt_drawlayer_cache_patch_t::x, and dt_drawlayer_cache_patch_t::y.

Referenced by dt_drawlayer_paint_rasterize_segment_to_buffer().

dt_drawlayer_brush_rasterize_dab_argb8()

gboolean dt_drawlayer_brush_rasterize_dab_argb8	(	const dt_drawlayer_brush_dab_t *	dab,
		uint8_t *	argb,
		const int	width,
		const int	height,
		const int	stride,
		const float	center_x,
		const float	center_y,
		const float	opacity_multiplier
	)

Render one dab to 8-bit ARGB surface for GUI cursor preview.

Rasterize a single dab preview into ARGB8 for GUI overlays.

Returns

TRUE on success.

References _clamp01(), _prepare_sprinkle_preview(), _sample_sprinkle_preview(), dt_drawlayer_brush_dab_t::display_color, dt_drawlayer_brush_profile_eval(), FALSE, height, dt_drawlayer_brush_dab_t::opacity, dt_drawlayer_brush_dab_t::radius, TRUE, width, and x.

Referenced by _ensure_cursor_stamp_surface().

dt_drawlayer_brush_rasterize_dab_rgbaf()

gboolean dt_drawlayer_brush_rasterize_dab_rgbaf	(	const dt_drawlayer_brush_dab_t *	dab,
		float *	rgba,
		int	width,
		int	height,
		float	center_x,
		float	center_y,
		float	opacity_multiplier,
		const float	background_rgb[3]
	)

Rasterize a single dab preview in linear float RGBA over an opaque background.

Parameters

dab	Input dab descriptor.
rgba	Destination float RGBA buffer (width*height*4), filled in linear display RGB.
width	Surface width.
height	Surface height.
center_x	Dab center X in surface coordinates.
center_y	Dab center Y in surface coordinates.
opacity_multiplier	Additional UI-time opacity scalar in [0,1].
background_rgb	Opaque linear RGB background color, or NULL for white.

Returns

TRUE on success, FALSE on invalid inputs.

References _clamp01(), _prepare_sprinkle_preview(), _sample_sprinkle_preview(), dt_drawlayer_brush_dab_t::color, dt_drawlayer_brush_profile_eval(), FALSE, height, i, dt_drawlayer_brush_dab_t::opacity, dt_drawlayer_brush_dab_t::radius, TRUE, width, and x.

Referenced by _render_brush_profile_cell().