A 2D RGBA image buffer. More...

#include <image.h>

Public Member Functions
	Image ()=default
	Construct an empty (0×0) image.

	Image (int w, int h)
	Construct an image of the given size, initialized to transparent black (0, 0, 0, 0).

void	set_pixel (int x, int y, uint8_t r, uint8_t g, uint8_t b, uint8_t a)
	Set a single pixel's RGBA value.

void	get_pixel (int x, int y, uint8_t &r, uint8_t &g, uint8_t &b, uint8_t &a) const
	Get a single pixel's RGBA value.

void	clear (uint8_t r, uint8_t g, uint8_t b, uint8_t a)
	Fill the entire image with an RGBA color (byte values 0–255).

void	clear_float (float r, float g, float b, float a)
	Fill the entire image with an RGBA color (float values 0.0–1.0).

Color	sample_bilinear (float u, float v) const
	Sample the image at texture coordinates (u, v) using bilinear interpolation.

Image	downsample_box (int factor) const
	Downsample the image by a factor using box filtering.

void	crop (int x, int y, int w, int h)
	Crop the image to a sub-rectangle.

void	merge (const Image &other, MergeDirection direction)
	Merge (concatenate) another image onto this one.

void	grow (int top, int bottom, int left, int right, const Color &background)
	Grow (pad) the image by adding borders.

void	rotate_90 (bool clockwise=true)
	Rotate the image by 90 degrees in-place.

void	scale (int new_width, int new_height)
	Scale (resize) the image to new dimensions in-place.

void	crop_to_content (CropContentDirection direction, const Color &background)
	Crop away uniform borders of a given background color.

void	apply_contrast (float contrast)
	Apply a contrast adjustment to the image.

bool	write_ppm (const std::string &filename) const
	Write the image as a PPM file (Portable Pixmap).

bool	write_bmp (const std::string &filename) const
	Write the image as a BMP file (Windows Bitmap).

bool	write_tga (const std::string &filename, bool use24bit=false) const
	Write the image as a TGA file (Truevision Targa).

bool	write_png (const std::string &filename) const
	Write the image as a PNG file.

void	pad_to_size (int target_w, int target_h, const Color &background)
	Pad the image to a target size, centering the content.

Static Public Member Functions
static Image	read_image (const std::string &path)
	Read an image from a file (PNG, BMP, TGA, JPEG, etc.).

Public Attributes
int	width = 0
	Image width in pixels.

int	height = 0
	Image height in pixels.

std::vector< uint8_t >	pixels
	Raw pixel data: RGBA bytes, row-major, bottom-left origin.

Detailed Description

A 2D RGBA image buffer.

Overview

The Image class stores pixels as 4 bytes per pixel (red, green, blue, alpha) in row-major order. Pixel (0, 0) is the bottom-left corner (matching OpenGL texture convention).

Images are used both as render targets (the output of the renderer) and as texture sources for textured meshes.

Construction

Image img(800, 600); // 800×600 blank (transparent black)

img.clear(1.0f, 1.0f, 1.0f, 1.0f); // fill with opaque white

scimesh::Image

A 2D RGBA image buffer.

Definition image.h:87

Saving

img.write_png("output.png");   // PNG (recommended)
img.write_ppm("output.ppm");   // PPM (simple text/binary format, for debugging)
img.write_bmp("output.bmp");   // BMP (for debugging)
img.write_tga("output.tga");   // TGA (uncompressed true-color, no dependencies)

See also: Mesh::texture, Renderer

Definition at line 87 of file image.h.

Constructor & Destructor Documentation

◆ Image() [1/2]

scimesh::Image::Image ( )

default

Construct an empty (0×0) image.

◆ Image() [2/2]

scimesh::Image::Image	(	int	w,
		int	h
	)

Construct an image of the given size, initialized to transparent black (0, 0, 0, 0).

Parameters

w	Width in pixels.
h	Height in pixels.

Definition at line 37 of file image.cpp.

Member Function Documentation

◆ apply_contrast()

void scimesh::Image::apply_contrast ( float contrast )

Apply a contrast adjustment to the image.

A value of 1.0 means no change. Values > 1.0 increase contrast; values < 1.0 reduce it (0.0 = uniform gray).

Parameters

contrast Contrast multiplier (1.0 = unchanged).

Example: img.apply_contrast(1.5f); // increase contrast

Definition at line 379 of file image.cpp.

◆ clear()

void scimesh::Image::clear	(	uint8_t	r,
		uint8_t	g,
		uint8_t	b,
		uint8_t	a
	)

Fill the entire image with an RGBA color (byte values 0–255).

Parameters

r	Red channel.
g	Green channel.
b	Blue channel.
a	Alpha channel.

Definition at line 61 of file image.cpp.

◆ clear_float()

void scimesh::Image::clear_float	(	float	r,
		float	g,
		float	b,
		float	a
	)

Fill the entire image with an RGBA color (float values 0.0–1.0).

This is a convenience wrapper that converts floats to bytes internally.

Parameters

r	Red channel (0.0–1.0).
g	Green channel (0.0–1.0).
b	Blue channel (0.0–1.0).
a	Alpha channel (0.0–1.0).

Definition at line 70 of file image.cpp.

◆ crop()

void scimesh::Image::crop	(	int	x,
		int	y,
		int	w,
		int	h
	)

Crop the image to a sub-rectangle.

The cropped region replaces the image in-place.

Parameters

x	Left edge of the crop region.
y	Bottom edge of the crop region.
w	Width of the crop region.
h	Height of the crop region.

Example: img.crop(100, 50, 400, 300); // keep a 400×300 region

Definition at line 110 of file image.cpp.

◆ crop_to_content()

void scimesh::Image::crop_to_content	(	CropContentDirection	direction,
		const Color &	background
	)

Crop away uniform borders of a given background color.

Removes rows/columns from the specified edges as long as every pixel in that row/column matches the background color (within tolerance).

Parameters

direction	Which edge(s) to crop.
background	The color to treat as "empty" border.

Example: img.crop_to_content(CropContentDirection::ALL, TRANSPARENT_BLACK);

// removes all transparent borders from all edges

scimesh::CropContentDirection::ALL
@ ALL
Crop all four edges.

scimesh::TRANSPARENT_BLACK
constexpr Color TRANSPARENT_BLACK
A fully transparent black color (0, 0, 0, 0).
Definition types.h:150

See also: CropContentDirection

Definition at line 273 of file image.cpp.

◆ downsample_box()

Image scimesh::Image::downsample_box ( int factor ) const

Downsample the image by a factor using box filtering.

Reduces the image size. Each output pixel is the average of a factor × factor block of input pixels. The width and height must be divisible by factor.

Parameters

factor Downsampling factor (e.g., 2 halves both dimensions).

Returns: A new, smaller Image.

Example: Image small = big.downsample_box(4); // ¼ width, ¼ height

scimesh::Image::downsample_box
Image downsample_box(int factor) const
Downsample the image by a factor using box filtering.
Definition image.cpp:77

Definition at line 77 of file image.cpp.

◆ get_pixel()

void scimesh::Image::get_pixel	(	int	x,
		int	y,
		uint8_t &	r,
		uint8_t &	g,
		uint8_t &	b,
		uint8_t &	a
	)		const

Get a single pixel's RGBA value.

Parameters

[in]	x	X coordinate (0 = left).
[in]	y	Y coordinate (0 = bottom).
[out]	r	Red channel (0–255).
[out]	g	Green channel (0–255).
[out]	b	Blue channel (0–255).
[out]	a	Alpha channel (0–255).

Definition at line 49 of file image.cpp.

◆ grow()

void scimesh::Image::grow	(	int	top,
		int	bottom,
		int	left,
		int	right,
		const Color &	background
	)

Grow (pad) the image by adding borders.

Adds top, bottom, left, right rows/columns filled with the given background color.

Parameters

top	Pixels to add above the image.
bottom	Pixels to add below the image.
left	Pixels to add left of the image.
right	Pixels to add right of the image.
background	Fill color for the new border.

Example: img.grow(10, 10, 20, 20, Color(1,1,1)); // add 10px top/bottom, 20px left/right

scimesh::Color
An RGBA color with floating-point components.
Definition types.h:88

Definition at line 197 of file image.cpp.

◆ merge()

void scimesh::Image::merge	(	const Image &	other,
		MergeDirection	direction
	)

Merge (concatenate) another image onto this one.

The two images must have compatible dimensions for the merge direction. For LEFT/RIGHT merges, both images must have the same height. For TOP/BOTTOM merges, both images must have the same width.

Parameters

other	The image to attach.
direction	Which side to attach to.

Example: Image left(400, 300), right(400, 300);

left.merge(right, MergeDirection::RIGHT);

// left is now 800×300

scimesh::MergeDirection::RIGHT
@ RIGHT
Attach other to the right side.

See also: MergeDirection

Definition at line 143 of file image.cpp.

◆ pad_to_size()

void scimesh::Image::pad_to_size	(	int	target_w,
		int	target_h,
		const Color &	background
	)

Pad the image to a target size, centering the content.

Adds borders filled with background so the image reaches target_w × target_h. Content stays pixel-perfect — no scaling. If the image is already at or larger than the target size, this is a no-op.

Parameters

target_w	Desired width in pixels.
target_h	Desired height in pixels.
background	Fill color for the added borders.

Example: Image small(400, 300);

small.pad_to_size(800, 600, Color(1,1,1));

// small is now 800×600, original content centered

See also: grow(), scale()

Definition at line 547 of file image.cpp.

◆ read_image()

Image scimesh::Image::read_image ( const std::string & path )

static

Read an image from a file (PNG, BMP, TGA, JPEG, etc.).

Uses stb_image internally, which auto-detects the format from the file header. Returns an empty (0×0) image on failure.

Parameters

path	Path to the image file.

Returns: The loaded Image, or empty Image on failure.

Example: Image img = Image::read_image("colorbar.png");

if (img.width == 0) { // handle error }

scimesh::Image::width
int width
Image width in pixels.
Definition image.h:89

scimesh::Image::read_image
static Image read_image(const std::string &path)
Read an image from a file (PNG, BMP, TGA, JPEG, etc.).
Definition image.cpp:533

Definition at line 533 of file image.cpp.

◆ rotate_90()

void scimesh::Image::rotate_90 ( bool clockwise = true )

Rotate the image by 90 degrees in-place.

Parameters

clockwise If true (default), rotate clockwise. Otherwise, counter-clockwise.

Example: img.rotate_90(); // clockwise

img.rotate_90(false); // counter-clockwise

Definition at line 228 of file image.cpp.

◆ sample_bilinear()

Color scimesh::Image::sample_bilinear	(	float	u,
		float	v
	)		const

Sample the image at texture coordinates (u, v) using bilinear interpolation.

Bilinear sampling blends the four nearest pixels, producing a smooth result when texture coordinates fall between pixel centers.

Parameters

u	Horizontal texture coordinate (0.0–1.0, 0 = left).
v	Vertical texture coordinate (0.0–1.0, 0 = bottom).

Returns: The interpolated Color.

Example: Color c = img.sample_bilinear(0.5f, 0.5f); // center of texture

Definition at line 351 of file image.cpp.

◆ scale()

void scimesh::Image::scale	(	int	new_width,
		int	new_height
	)

Scale (resize) the image to new dimensions in-place.

Uses bilinear interpolation for smooth results.

Parameters

new_width	Target width in pixels.
new_height	Target height in pixels.

Example: img.scale(1600, 1200); // upscale to 1600×1200

Definition at line 251 of file image.cpp.

◆ set_pixel()

void scimesh::Image::set_pixel	(	int	x,
		int	y,
		uint8_t	r,
		uint8_t	g,
		uint8_t	b,
		uint8_t	a
	)

Set a single pixel's RGBA value.

Parameters

x	X coordinate (0 = left).
y	Y coordinate (0 = bottom).
r	Red channel (0–255).
g	Green channel (0–255).
b	Blue channel (0–255).
a	Alpha channel (0–255, 255 = fully opaque).

Definition at line 39 of file image.cpp.

◆ write_bmp()

bool scimesh::Image::write_bmp ( const std::string & filename ) const

Write the image as a BMP file (Windows Bitmap).

BMP is a simple, uncompressed format. No external libraries needed.

Parameters

filename Output file path (should end with .bmp).

Returns: true on success.

See also: write_png(), write_ppm()

Definition at line 405 of file image.cpp.

◆ write_png()

bool scimesh::Image::write_png ( const std::string & filename ) const

Write the image as a PNG file.

PNG is the recommended output format for publication-quality results. Uses stb_image_write internally.

Parameters

filename Output file path (should end with .png).

Returns: true on success.

Example: Image result = renderer.render_mesh(mesh, camera, opts);

result.write_png("rendering.png");

scimesh::Image::write_png
bool write_png(const std::string &filename) const
Write the image as a PNG file.
Definition image.cpp:521

See also: write_ppm(), write_bmp()

Definition at line 521 of file image.cpp.

◆ write_ppm()

bool scimesh::Image::write_ppm ( const std::string & filename ) const

Write the image as a PPM file (Portable Pixmap).

PPM is a simple, uncompressed format useful for debugging and testing. No external libraries are needed.

Parameters

filename Output file path (should end with .ppm).

Returns: true on success.

See also: write_png(), write_bmp()

Definition at line 392 of file image.cpp.

◆ write_tga()

bool scimesh::Image::write_tga	(	const std::string &	filename,
		bool	use24bit = `false`
	)		const

Write the image as a TGA file (Truevision Targa).

Writes an uncompressed true-color TGA file (image type 2) using scimesh's own implementation (no external libraries). The header declares a top-left origin, matching the pixel layout produced by the renderer. Pixel data is stored BGR(A) per the TGA spec, so red and blue channels are swapped on write.

Parameters

filename	Output file path (should end with `.tga`).
use24bit	If `true`, write 24-bit RGB (no alpha channel). Default `false` writes 32-bit RGBA.

Returns: true on success.

See also: write_png(), write_bmp()

Definition at line 471 of file image.cpp.

Member Data Documentation

◆ height

int scimesh::Image::height = 0

Image height in pixels.

Definition at line 92 of file image.h.

◆ pixels

std::vector<uint8_t> scimesh::Image::pixels

Raw pixel data: RGBA bytes, row-major, bottom-left origin.

Size is width * height * 4 bytes. Pixel at (x, y) is at offset (y * width + x) * 4.

Definition at line 98 of file image.h.

◆ width

int scimesh::Image::width = 0

Image width in pixels.

Definition at line 89 of file image.h.

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

src/core/scimesh/image.h
src/core/image.cpp

Public Member Functions

Static Public Member Functions

Public Attributes

Detailed Description

Overview

Construction

Saving

Constructor & Destructor Documentation

◆ Image() [1/2]

◆ Image() [2/2]

Member Function Documentation

◆ apply_contrast()

◆ clear()

◆ clear_float()

◆ crop()

◆ crop_to_content()

◆ downsample_box()

◆ get_pixel()

◆ grow()

◆ merge()

◆ pad_to_size()

◆ read_image()

◆ rotate_90()

◆ sample_bilinear()

◆ scale()

◆ set_pixel()

◆ write_bmp()

◆ write_png()

◆ write_ppm()

◆ write_tga()

Member Data Documentation

◆ height

◆ pixels

◆ width