API Drawing

Drawing

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Namespace: acl::draw

Draw lines / rectangles / circles / text on an image. All entry points are non-templated, uint8_t only, supporting 1ch / 3ch / 4ch.

Tier: Starter+
Channels: 1 / 3 / 4
Inplace: drawn directly on the source image (img is both input and output)

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drawLine

Draw a line segment using the Bresenham algorithm. Tier: Starter+
Channels: 1ch / 3ch / 4ch
Inplace: supported (writes onto the provided image buffer)
Types:

Template parameter	Allowed types	Constraint
T	uint8_t	—

int drawLine(
    uint8_t* img,
    int width, int height, int cn, int stride,
    int x0, int y0, int x1, int y1,
    const uint8_t* color,
    int thickness = 1);

Parameter	Type	Meaning	Default
img	uint8_t*	Destination image (drawn in place)	non-null
width, height	int	Image size	> 0
cn	int	Channel count	1 / 3 / 4
stride	int	Bytes per row	0 = width * cn
x0, y0, x1, y1	int	Line segment start / end points	—
color	const uint8_t*	Color-value array of length cn	non-null
thickness	int	Line width (pixels)	1

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drawRect

Draw a rectangle (outline or filled). Tier: Starter+
Channels: 1ch / 3ch / 4ch
Inplace: supported (writes onto the provided image buffer)
Types:

Template parameter	Allowed types	Constraint
T	uint8_t	—

int drawRect(
    uint8_t* img,
    int imgW, int imgH, int cn, int stride,
    int x, int y, int w, int h,
    const uint8_t* color,
    int thickness = 1);

Parameter	Type	Meaning	Default
x, y	int	Rectangle top-left	—
w, h	int	Rectangle width / height	—
thickness	int	Line width; -1 = filled rectangle	1

Other parameters are the same as drawLine.

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drawCircle

Draw a circle using the midpoint circle algorithm (outline or filled). Tier: Starter+
Channels: 1ch / 3ch / 4ch
Inplace: supported (writes onto the provided image buffer)
Types:

Template parameter	Allowed types	Constraint
T	uint8_t	—

int drawCircle(
    uint8_t* img,
    int width, int height, int cn, int stride,
    int cx, int cy, int radius,
    const uint8_t* color,
    int thickness = 1);

Parameter	Type	Meaning	Default
cx, cy	int	Circle center	—
radius	int	Radius	≥ 0
thickness	int	Line width; -1 = filled circle	1

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putText

Render ASCII text using the built-in 8×16 bitmap font. Supports newlines \n; the font size scales linearly via scale. Tier: Starter+
Channels: 1ch / 3ch / 4ch
Inplace: supported (writes onto the provided image buffer)
Types:

Template parameter	Allowed types	Constraint
T	uint8_t	—

int putText(
    uint8_t* img,
    int width, int height, int cn, int stride,
    const char* text,
    int x, int y,
    const uint8_t* color,
    int scale = 1);

Parameter	Type	Meaning	Default
text	const char*	\0-terminated ASCII string	non-null
x, y	int	Text top-left coordinates	—
scale	int	Font-size multiplier (1 = 8×16, 2 = 16×32 …)	1

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Example

uint8_t img[1920*1080*3] = {};
uint8_t red[3]  = { 255, 0, 0 };
uint8_t blue[3] = { 0, 0, 255 };

acl::draw::drawLine(img, 1920, 1080, 3, 0, 100, 100, 500, 500, red, 2);
acl::draw::drawRect(img, 1920, 1080, 3, 0, 200, 200, 300, 150, blue, -1);
acl::draw::drawCircle(img, 1920, 1080, 3, 0, 960, 540, 80, red, 3);
acl::draw::putText(img, 1920, 1080, 3, 0, "Hello\nWorld", 50, 50, blue, 2);