Support-routines for the SDL-graphics-library. More...

#include "sdl/utils.hpp"
#include "sdl/rect.hpp"
#include "color.hpp"
#include "xBRZ/xbrz.hpp"
#include <algorithm>
#include <cassert>
#include <cstring>
#include <iostream>
#include <boost/circular_buffer.hpp>
#include <boost/math/constants/constants.hpp>

Include dependency graph for utils.cpp:

Go to the source code of this file.

Functions
version_info	sdl_get_version ()

surface	stretch_surface_horizontal (const surface &surf, const unsigned w)
	Stretches a surface in the horizontal direction. More...

surface	stretch_surface_vertical (const surface &surf, const unsigned h)
	Stretches a surface in the vertical direction. More...

surface	scale_surface_xbrz (const surface &surf, std::size_t z)
	Scale a surface using xBRZ algorithm. More...

surface	scale_surface_nn (const surface &surf, int w, int h)
	Scale a surface using the nearest neighbor algorithm (provided by xBRZ lib) More...

surface	scale_surface (const surface &surf, int w, int h)
	Scale a surface using alpha-weighted modified bilinear filtering Note: causes artifacts with alpha gradients, for example in some portraits. More...

surface	scale_surface_legacy (const surface &surf, int w, int h)
	Scale a surface using simple bilinear filtering (discarding rgb from source pixels with 0 alpha) More...

surface	scale_surface_sharp (const surface &surf, int w, int h)
	Scale a surface using modified nearest neighbour algorithm. More...

surface	tile_surface (const surface &surf, int w, int h, bool centered)
	Tile a surface. More...

surface	adjust_surface_color (const surface &surf, int red, int green, int blue)

surface	greyscale_image (const surface &surf)

surface	monochrome_image (const surface &surf, const int threshold)

surface	sepia_image (const surface &surf)

surface	negative_image (const surface &surf, const int thresholdR, const int thresholdG, const int thresholdB)

surface	alpha_to_greyscale (const surface &surf)

surface	wipe_alpha (const surface &surf)

surface	shadow_image (const surface &surf)
	create an heavy shadow of the image, by blurring, increasing alpha and darkening More...

surface	swap_channels_image (const surface &surf, channel r, channel g, channel b, channel a)

surface	recolor_image (surface surf, const color_range_map &map_rgb)
	Recolors a surface using a map with source and converted palette values. More...

surface	brighten_image (const surface &surf, fixed_t amount)

void	adjust_surface_alpha (surface &surf, fixed_t amount)

surface	adjust_surface_alpha_add (const surface &surf, int amount)

surface	mask_surface (const surface &surf, const surface &mask, bool *empty_result, const std::string &filename)
	Applies a mask on a surface. More...

bool	in_mask_surface (const surface &surf, const surface &mask)
	Check if a surface fit into a mask. More...

surface	submerge_alpha (const surface &surf, int depth, float alpha_base, float alpha_delta)
	Progressively reduce alpha of bottom part of the surface. More...

surface	light_surface (const surface &surf, const surface &lightmap)
	Light surf using lightmap. More...

surface	blur_surface (const surface &surf, int depth)
	Cross-fades a surface. More...

void	blur_surface (surface &surf, SDL_Rect rect, int depth)
	Cross-fades a surface in place. More...

surface	blur_alpha_surface (const surface &surf, int depth)
	Cross-fades a surface with alpha channel. More...

surface	cut_surface (const surface &surf, const SDL_Rect &r)
	Cuts a rectangle from a surface. More...

surface	blend_surface (const surface &surf, const double amount, const color_t color)
	Blends a surface with a color. More...

surface	rotate_any_surface (const surface &surf, float angle, int zoom, int offset)
	Rotates a surface by any degrees. More...

void	put_pixel (const surface &surf, surface_lock &surf_lock, int x, int y, uint32_t pixel)
	Helper methods for setting/getting a single pixel in an image. More...

uint32_t	get_pixel (const surface &surf, const const_surface_lock &surf_lock, int x, int y)

surface	rotate_180_surface (const surface &surf)
	Rotates a surface 180 degrees. More...

surface	rotate_90_surface (const surface &surf, bool clockwise)
	Rotates a surface 90 degrees. More...

surface	flip_surface (const surface &surf)

surface	flop_surface (const surface &surf)

void	blit_surface (const surface &surf, const SDL_Rect srcrect, surface &dst, const SDL_Rect dstrect)
	Replacement for sdl_blit. More...

surface	get_surface_portion (const surface &src, SDL_Rect &area)
	Get a portion of the screen. More...

SDL_Rect	get_non_transparent_portion (const surface &surf)

void	draw_centered_on_background (surface surf, const SDL_Rect &rect, const color_t &color, surface target)

Detailed Description

Support-routines for the SDL-graphics-library.

Definition in file utils.cpp.

Function Documentation

◆ adjust_surface_alpha()

void adjust_surface_alpha	(	surface &	surf,
		fixed_t	amount
	)

Definition at line 1086 of file utils.cpp.

Referenced by gui::textbox::append_text(), font::floating_label::create_surface(), gui::textbox::draw_contents(), game_display::new_turn(), display::render_image(), editor::mouse_action_item::set_item_mouse_overlay(), editor::mouse_action_map_label::set_mouse_overlay(), editor::mouse_action_village::set_mouse_overlay(), editor::mouse_action_select::set_mouse_overlay(), editor::mouse_action_paste::set_mouse_overlay(), editor::mouse_action_starting_position::set_mouse_overlay(), editor::mouse_action::set_terrain_mouse_overlay(), and editor::mouse_action_unit::set_unit_mouse_overlay().

◆ adjust_surface_alpha_add()

surface adjust_surface_alpha_add	(	const surface &	surf,
		int	amount
	)

Definition at line 1095 of file utils.cpp.

References b, surface::clone(), g, and surface_locker< T >::pixels().

Referenced by font::floating_label::undraw().

◆ adjust_surface_color()

surface adjust_surface_color	(	const surface &	surf,
		int	red,
		int	green,
		int	blue
	)

Definition at line 595 of file utils.cpp.

References b, surface::clone(), g, and surface_locker< T >::pixels().

Referenced by image::apply_light(), image::get_tod_colored(), image::getMinimap(), image::cs_modification::operator()(), and sdl_copy_portion().

◆ alpha_to_greyscale()

surface alpha_to_greyscale ( const surface & surf )

Definition at line 810 of file utils.cpp.

References surface::clone(), and surface_locker< T >::pixels().

Referenced by image::plot_alpha_modification::operator()(), and sdl_copy_portion().

◆ blend_surface()

surface blend_surface	(	const surface &	surf,
		const double	amount,
		const color_t	color
	)

Blends a surface with a color.

Every pixel in the surface will be blended with the color given. The final color of a pixel is amount * color + (1 - amount) * original.

Parameters

surf	The surface to blend.
amount	The amount of the new color is determined by `color`. Must be a number in the range [0, 1].
color	The color to blend width, note its alpha channel is ignored.

Returns: The blended surface.

Definition at line 1716 of file utils.cpp.

References a, color_t::b, b, surface::clone(), g, color_t::g, surface_locker< T >::pixels(), and color_t::r.

Referenced by image::blend_modification::operator()(), and display::render_image().

◆ blit_surface()

void blit_surface	(	const surface &	src,
		const SDL_Rect *	srcrect,
		surface &	dst,
		const SDL_Rect *	dstrect
	)

Replacement for sdl_blit.

sdl_blit has problems with blitting partly transparent surfaces so this is a replacement. It ignores the SDL_SRCALPHA and SDL_SRCCOLORKEY flags. src and dst will have the SDL_RLEACCEL flag removed. The return value of SDL_BlistSurface is normally ignored so no return value. The rectangles are const and will not be modified.

Precondition: src contains a valid canvas.; dst contains a valid neutral canvas.; The caller must make sure the src fits on the dst.

Parameters

src	The surface to blit.
srcrect	The region of the surface to blit
dst	The surface to blit on.
dstrect	The offset to blit the surface on, only x and y are used.

Definition at line 2009 of file utils.cpp.

References surface::is_neutral(), surface_locker< T >::pixels(), and w.

Referenced by CVideo::current_refresh_rate(), gui2::image_shape::draw(), gui2::text_shape::draw(), and font::render_text().

◆ blur_alpha_surface()

surface blur_alpha_surface	(	const surface &	surf,
		int	depth = `1`
	)

Cross-fades a surface with alpha channel.

Parameters

surf	The source surface.
depth	The depth of the blurring.

Returns: A new, blurred, neutral surface.

Definition at line 1511 of file utils.cpp.

References surface::clone(), p, and surface_locker< T >::pixels().

Referenced by image::bl_modification::operator()(), and shadow_image().

◆ blur_surface() [1/2]

surface blur_surface	(	const surface &	surf,
		int	depth = `1`
	)

Cross-fades a surface.

Parameters

surf	The source surface.
depth	The depth of the blurring.

Returns: A new, blurred, neutral surface.

Definition at line 1376 of file utils.cpp.

References blur_surface(), and surface::clone().

Referenced by gui2::canvas::blit(), blur_surface(), and gui::dialog_frame::draw_background().

◆ blur_surface() [2/2]

void blur_surface	(	surface &	surf,
		SDL_Rect	rect,
		int	depth = `1`
	)

Cross-fades a surface in place.

Parameters

surf	The surface to blur, must have 32 bits per pixel.
rect	The part of the surface to blur.
depth	The depth of the blurring.

Definition at line 1395 of file utils.cpp.

References p, and surface_locker< T >::pixels().

◆ brighten_image()

surface brighten_image	(	const surface &	surf,
		fixed_t	amount
	)

Definition at line 1044 of file utils.cpp.

References b, surface::clone(), fxpmult, g, and surface_locker< T >::pixels().

Referenced by image::get_brightened(), and display::render_image().

◆ cut_surface()

surface cut_surface	(	const surface &	surf,
		const SDL_Rect &	r
	)

Cuts a rectangle from a surface.

Definition at line 1658 of file utils.cpp.

References surface_locker< T >::pixels(), and utf8::size().

Referenced by image::load_image_sub_file(), and image::crop_modification::operator()().

◆ draw_centered_on_background()

void draw_centered_on_background	(	surface	surf,
		const SDL_Rect &	rect,
		const color_t &	color,
		surface	target
	)

Definition at line 2272 of file utils.cpp.

References color_t::a, color_t::b, sdl::fill_surface_rect(), color_t::g, color_t::r, and sdl_blit().

Referenced by display::draw_minimap().

◆ flip_surface()

surface flip_surface ( const surface & surf )

Definition at line 1951 of file utils.cpp.

References surface::clone(), surface_locker< T >::pixels(), and swap().

Referenced by gui2::image_shape::draw(), image::fl_modification::operator()(), and image::reverse_image().

◆ flop_surface()

surface flop_surface ( const surface & surf )

Definition at line 1980 of file utils.cpp.

References surface::clone(), surface_locker< T >::pixels(), and swap().

Referenced by image::fl_modification::operator()(), halo::halo_impl::effect::render(), and display::render_image().

◆ get_non_transparent_portion()

SDL_Rect get_non_transparent_portion ( const surface & surf )

Definition at line 2203 of file utils.cpp.

References surface::clone(), n, and surface_locker< T >::pixels().

Referenced by display::draw_image_for_report().

◆ get_pixel()

uint32_t get_pixel	(	const surface &	surf,
		const const_surface_lock &	surf_lock,
		int	x,
		int	y
	)

Definition at line 1851 of file utils.cpp.

References surface_locker< T >::pixels().

Referenced by rotate_any_surface().

◆ get_surface_portion()

surface get_surface_portion	(	const surface &	surf,
		SDL_Rect &	rect
	)

Get a portion of the screen.

Send nullptr if the portion is outside of the screen.

Parameters

surf	The source surface.
rect	The portion of the source surface to copy.

Returns: A surface containing the portion of the source. No RLE or Alpha bits are set.

Return values

0	if error or the portion is outside of the surface.

Definition at line 2157 of file utils.cpp.

References sdl_copy_portion().

Referenced by gui2::canvas::blit(), gui2::window::draw(), gui::dialog_frame::draw_background(), display::draw_image_for_report(), display::refresh_report(), halo::halo_impl::effect::render(), and surface_restorer::update().

◆ greyscale_image()

surface greyscale_image ( const surface & surf )

Definition at line 640 of file utils.cpp.

References b, surface::clone(), g, and surface_locker< T >::pixels().

Referenced by image::gs_modification::operator()(), display::render_image(), and sdl_copy_portion().

◆ in_mask_surface()

bool in_mask_surface	(	const surface &	surf,
		const surface &	mask
	)

Check if a surface fit into a mask.

Definition at line 1202 of file utils.cpp.

References surface::clone(), and surface_locker< T >::pixels().

Referenced by image::is_in_hex().

◆ light_surface()

surface light_surface	(	const surface &	surf,
		const surface &	lightmap
	)

Light surf using lightmap.

Parameters

surf	The source surface.
lightmap	add/subtract this color to surf but RGB values are converted to (X-128)*2 to cover the full (-256,256) spectrum. Should already be neutral

Definition at line 1310 of file utils.cpp.

References b, surface::clone(), g, and surface_locker< T >::pixels().

Referenced by image::apply_light(), and image::light_modification::operator()().

◆ mask_surface()

surface mask_surface	(	const surface &	surf,
		const surface &	mask,
		bool *	empty_result = `nullptr`,
		const std::string &	filename = `std::string()`
	)

Applies a mask on a surface.

Definition at line 1133 of file utils.cpp.

References b, surface::clone(), g, and surface_locker< T >::pixels().

Referenced by image::get_hexed(), image::is_empty_hex(), image::load_image_sub_file(), image::mask_modification::operator()(), and editor::mouse_action::set_terrain_mouse_overlay().

◆ monochrome_image()

surface monochrome_image	(	const surface &	surf,
		const int	threshold
	)

Definition at line 685 of file utils.cpp.

References b, surface::clone(), g, and surface_locker< T >::pixels().

Referenced by image::bw_modification::operator()(), and sdl_copy_portion().

◆ negative_image()

surface negative_image	(	const surface &	surf,
		const int	thresholdR,
		const int	thresholdG,
		const int	thresholdB
	)

Definition at line 767 of file utils.cpp.

References b, surface::clone(), g, and surface_locker< T >::pixels().

Referenced by image::negative_modification::operator()(), and sdl_copy_portion().

◆ put_pixel()

void put_pixel	(	const surface &	surf,
		surface_lock &	surf_lock,
		int	x,
		int	y,
		uint32_t	pixel
	)

Helper methods for setting/getting a single pixel in an image.

Lifted from http://sdl.beuc.net/sdl.wiki/Pixel_Access

Parameters

surf	The image to get or receive the pixel from.
surf_lock	The locked surface to make sure the pointers are valid.
x	The position in the row of the pixel.
y	The row of the pixel.

Definition at line 1820 of file utils.cpp.

References surface_locker< T >::pixels().

Referenced by rotate_any_surface().

◆ recolor_image()

surface recolor_image	(	surface	surf,
		const color_range_map &	map_rgb
	)

Recolors a surface using a map with source and converted palette values.

This is most often used for team-coloring.

Parameters

surf	The source surface.
map_rgb	Map of color values, with the keys corresponding to the source palette, and the values to the recolored palette.

Returns: A recolored surface, or a null surface if there are problems with the source.

Definition at line 1005 of file utils.cpp.

References surface::clone(), color_t::from_argb_bytes(), i, and surface_locker< T >::pixels().

Referenced by image::rc_modification::operator()().

◆ rotate_180_surface()

surface rotate_180_surface ( const surface & surf )

Rotates a surface 180 degrees.

Parameters

surf	The surface to rotate.

Returns: The rotated surface.

Definition at line 1874 of file utils.cpp.

References surface::clone(), is_odd(), surface_locker< T >::pixels(), and swap().

Referenced by image::fl_modification::operator()(), and image::rotate_modification::operator()().

◆ rotate_90_surface()

surface rotate_90_surface	(	const surface &	surf,
		bool	clockwise
	)

Rotates a surface 90 degrees.

Parameters

surf	The surface to rotate.
clockwise	Whether the rotation should be clockwise (true) or counter-clockwise (false).

Returns: The rotated surface.

Definition at line 1916 of file utils.cpp.

References surface_locker< T >::pixels().

Referenced by image::rotate_modification::operator()().

◆ rotate_any_surface()

surface rotate_any_surface	(	const surface &	surf,
		float	angle,
		int	zoom,
		int	offset
	)

Rotates a surface by any degrees.

Precondition: zoom >= offset Otherwise

Returns: will have empty pixels.

Precondition: offset > 0 Otherwise the procedure will not return.

Parameters

surf	The surface to rotate.
angle	The angle of rotation.
zoom	Which zoom level to use for calculating the result.
offset	Pixel offset when scanning the zoomed source.

Returns: The rotated surface.

Definition at line 1763 of file utils.cpp.

References get_pixel(), put_pixel(), xbrz::scale(), and scale_surface().

Referenced by image::rotate_modification::operator()().

◆ scale_surface()

surface scale_surface	(	const surface &	surf,
		int	w,
		int	h
	)

Scale a surface using alpha-weighted modified bilinear filtering Note: causes artifacts with alpha gradients, for example in some portraits.

Parameters

surf	The source surface.
w	The width of the resulting surface.
h	The height of the resulting surface.

Returns: A surface containing the scaled version of the source.

Return values

0	Returned upon error.
surf	Returned if w == surf->w and h == surf->h.

Definition at line 196 of file utils.cpp.

References a, b, e, ftofxp, fxpdiv, fxptoi, g, h, n, surface_locker< T >::pixels(), s, and w.

◆ scale_surface_legacy()

surface scale_surface_legacy	(	const surface &	surf,
		int	w,
		int	h
	)

Scale a surface using simple bilinear filtering (discarding rgb from source pixels with 0 alpha)

Parameters

surf	The source surface.
w	The width of the resulting surface.
h	The height of the resulting surface.

Returns: A surface containing the scaled version of the source.

Return values

0	Returned upon error.
surf	Returned if w == surf->w and h == surf->h.

Definition at line 325 of file utils.cpp.

References a, b, ftofxp, fxpdiv, fxptoi, g, h, surface_locker< T >::pixels(), and w.

Referenced by gui2::image_shape::draw(), image::scale_modification::operator()(), and sdl_copy_portion().

◆ scale_surface_nn()

surface scale_surface_nn	(	const surface &	surf,
		int	w,
		int	h
	)

Scale a surface using the nearest neighbor algorithm (provided by xBRZ lib)

Parameters

surf	The sources surface
w	The width of the resulting surface.
h	The height of the resulting surface.

Returns: The rescaled surface.

Definition at line 159 of file utils.cpp.

References h, xbrz::nearestNeighborScale(), surface_locker< T >::pixels(), and w.

Referenced by sdl_copy_portion(), and image::select_algorithm().

◆ scale_surface_sharp()

surface scale_surface_sharp	(	const surface &	surf,
		int	w,
		int	h
	)

Scale a surface using modified nearest neighbour algorithm.

Use only if preserving sharp edges is a priority (e.g. minimap).

Parameters

surf	The source surface.
w	The width of the resulting surface.
h	The height of the resulting surface.

Returns: A surface containing the scaled version of the source.

Return values

0	Returned upon error.
surf	Returned if w == surf->w and h == surf->h.

Definition at line 462 of file utils.cpp.

References a, b, g, h, surface_locker< T >::pixels(), and w.

Referenced by image::getMinimap(), image::scale_modification::operator()(), and sdl_copy_portion().

◆ scale_surface_xbrz()

surface scale_surface_xbrz	(	const surface &	surf,
		std::size_t	z
	)

Scale a surface using xBRZ algorithm.

Parameters

surf	The source surface
z	The scaling factor. Should be an integer 2-5 (1 is tolerated).

Returns: The scaled surface

Definition at line 122 of file utils.cpp.

References surface_locker< T >::pixels(), and xbrz::scale().

Referenced by image::xbrz_modification::operator()(), image::scale_xbrz_helper(), and sdl_copy_portion().

◆ sdl_get_version()

version_info sdl_get_version ( )

Definition at line 33 of file utils.cpp.

Referenced by surface::free_surface(), CVideo::update_framebuffer(), and CVideo::~CVideo().

◆ sepia_image()

surface sepia_image ( const surface & surf )

Definition at line 725 of file utils.cpp.

References b, surface::clone(), g, and surface_locker< T >::pixels().

Referenced by image::sepia_modification::operator()(), and sdl_copy_portion().

◆ shadow_image()

surface shadow_image ( const surface & surf )

create an heavy shadow of the image, by blurring, increasing alpha and darkening

Definition at line 866 of file utils.cpp.

References blur_alpha_surface(), and surface_locker< T >::pixels().

Referenced by font::floating_label::create_surface(), and sdl_copy_portion().

◆ stretch_surface_horizontal()

surface stretch_surface_horizontal	(	const surface &	surf,
		const unsigned	w
	)

Stretches a surface in the horizontal direction.

The stretches a surface it uses the first pixel in the horizontal direction of the original surface and copies that to the destination. This means only the first column of the original is used for the destination.

Parameters

surf	The source surface.
w	The width of the resulting surface.

Returns: A surface. returned.

Return values

0	Returned upon error.
surf	Returned if w == surf->w.

Definition at line 40 of file utils.cpp.

References surface_locker< T >::pixels(), and w.

Referenced by gui2::image_shape::draw(), and sdl_copy_portion().

◆ stretch_surface_vertical()

surface stretch_surface_vertical	(	const surface &	surf,
		const unsigned	h
	)

Stretches a surface in the vertical direction.

The stretches a surface it uses the first pixel in the vertical direction of the original surface and copies that to the destination. This means only the first row of the original is used for the destination.

Parameters

surf	The source surface.
h	The height of the resulting surface.

Returns: A surface. returned.

Return values

surf	Returned if h == surf->h.

Definition at line 82 of file utils.cpp.

References h, and surface_locker< T >::pixels().

Referenced by gui2::image_shape::draw(), and sdl_copy_portion().

◆ submerge_alpha()

surface submerge_alpha	(	const surface &	surf,
		int	depth,
		float	alpha_base,
		float	alpha_delta
	)

Progressively reduce alpha of bottom part of the surface.

Parameters

surf	The source surface.
depth	The height of the bottom part in pixels
alpha_base	The alpha adjustment at the interface
alpha_delta	The alpha adjustment reduction rate by pixel depth

Definition at line 1248 of file utils.cpp.

References a, b, surface::clone(), d, ftofxp, fxpmult, g, and surface_locker< T >::pixels().

Referenced by display::render_image().

◆ swap_channels_image()

surface swap_channels_image	(	const surface &	surf,
		channel	r,
		channel	g,
		channel	b,
		channel	a
	)

Definition at line 903 of file utils.cpp.

References ALPHA, BLUE, surface::clone(), GREEN, surface_locker< T >::pixels(), and RED.

Referenced by image::swap_modification::operator()().

◆ tile_surface()

surface tile_surface	(	const surface &	surf,
		int	w,
		int	h,
		bool	centered = `true`
	)

Tile a surface.

Parameters

surf	The source surface.
w	The width of the resulting surface.
h	The height of the resulting surface.
centered	Whether to tile from the center outwards or from the top left (origin).

Returns: A surface containing the tiled version of the source.

Return values

0	Returned upon error
surf	Returned if w == surf->w and h == surf->h.

Definition at line 552 of file utils.cpp.

References h, i, surface_locker< T >::pixels(), sw, and w.

Referenced by gui2::image_shape::draw(), draw_panel(), and sdl_copy_portion().

◆ wipe_alpha()

surface wipe_alpha ( const surface & surf )

Definition at line 838 of file utils.cpp.

References surface::clone(), and surface_locker< T >::pixels().

Referenced by image::wipe_alpha_modification::operator()(), and sdl_copy_portion().

Functions

Detailed Description

Function Documentation

◆ adjust_surface_alpha()

◆ adjust_surface_alpha_add()

◆ adjust_surface_color()

◆ alpha_to_greyscale()

◆ blend_surface()

◆ blit_surface()

◆ blur_alpha_surface()

◆ blur_surface() [1/2]

◆ blur_surface() [2/2]

◆ brighten_image()

◆ cut_surface()

◆ draw_centered_on_background()

◆ flip_surface()

◆ flop_surface()

◆ get_non_transparent_portion()

◆ get_pixel()

◆ get_surface_portion()

◆ greyscale_image()

◆ in_mask_surface()

◆ light_surface()

◆ mask_surface()

◆ monochrome_image()

◆ negative_image()

◆ put_pixel()

◆ recolor_image()

◆ rotate_180_surface()

◆ rotate_90_surface()

◆ rotate_any_surface()

◆ scale_surface()

◆ scale_surface_legacy()

◆ scale_surface_nn()

◆ scale_surface_sharp()

◆ scale_surface_xbrz()

◆ sdl_get_version()

◆ sepia_image()

◆ shadow_image()

◆ stretch_surface_horizontal()

◆ stretch_surface_vertical()

◆ submerge_alpha()

◆ swap_channels_image()

◆ tile_surface()

◆ wipe_alpha()