Draw Module

The draw module provides functions for drawing shapes and text on images with a more user-friendly interface than OpenCV’s native drawing functions.

Drawing functions for computer vision applications.

This module provides a collection of drawing functions that wrap OpenCV’s drawing capabilities with a more user-friendly interface. All functions support relative coordinates, automatic color handling, and other conveniences.

Functions:

rectangle: Draw a rectangle on an image. polylines: Draw connected line segments on an image. fill_poly: Draw a filled polygon on an image. circle: Draw a circle on an image. point: Draw a point (filled circle) on an image. points: Draw multiple points on an image. line: Draw a line on an image. hline: Draw a horizontal line on an image. vline: Draw a vertical line on an image. text: Draw text on an image. rectangles: Draw multiple rectangles on an image. arrow: Draw an arrowed line on an image (experimental). ellipse: Draw an ellipse on an image (experimental). marker: Draw a marker on an image (experimental). getTextSize: Calculate the size of a text string (experimental).

Constants:

COLORS: List of named colors available for use in drawing functions.

cv3.draw.rectangle(img, x0, y0, x1, y1, mode='xyxy', rel=None, color=None, t=None, line_type=None, fill=None, copy=False)[source]

Draw a rectangle on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • x0 (int or float) – X-coordinate of the first point.

  • y0 (int or float) – Y-coordinate of the first point.

  • x1 (int or float) – X-coordinate of the second point.

  • y1 (int or float) – Y-coordinate of the second point.

  • mode (str, optional) – Coordinate mode. One of ‘xyxy’, ‘xywh’, ‘ccwh’. Defaults to ‘xyxy’.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the rectangle (default: opt.COLOR).

  • t – Thickness of the rectangle lines (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • fill (bool, optional) – Whether to fill the rectangle. If True, draws a filled rectangle regardless of thickness. If False, draws an outlined rectangle. If None, uses the thickness parameter to determine fill behavior. Defaults to None.

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the rectangle drawn on it.

Return type:

numpy.ndarray

Note

The coordinate modes are: - ‘xyxy’: Two corner points (x0, y0) and (x1, y1) - ‘xywh’: Top-left corner (x0, y0) and width (x1), height (y1) - ‘ccwh’: Center point (x0, y0) and width (x1), height (y1)

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

When fill=True, the rectangle is filled regardless of the thickness value. When fill=False, the rectangle is outlined with the specified thickness. When fill=None (default), the rectangle is filled if t=-1, otherwise outlined.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw a rectangle using absolute coordinates
>>> img = cv3.rectangle(img, 10, 10, 90, 90, color='red', t=2)
>>> # Draw a filled rectangle
>>> img = cv3.rectangle(img, 20, 20, 80, 80, color='blue', fill=True)
>>> # Draw a rectangle using relative coordinates
>>> img = cv3.rectangle(img, 0.2, 0.2, 0.8, 0.8, rel=True, color='green')
>>> # Draw a rectangle using xywh mode
>>> img = cv3.rectangle(img, 10, 10, 80, 80, mode='xywh', color='yellow')
cv3.draw.polylines(img, pts, is_closed=False, rel=None, color=None, t=None, line_type=None, copy=False)[source]

Draw polylines on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • pts (array-like) – Points defining the polylines. Can be a numpy array, list of lists, or tuple of tuples with shape (N, 2) where N is the number of points.

  • is_closed (bool, optional) – Whether to close the polyline by connecting the last point to the first. Defaults to False.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the polylines (default: opt.COLOR).

  • t – Thickness of the lines (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the polylines drawn on it.

Return type:

numpy.ndarray

Note

Points can be specified in various formats: - List of [x, y] coordinates: [[x1, y1], [x2, y2], …] - Tuple of (x, y) coordinates: ((x1, y1), (x2, y2), …) - Flattened list: [x1, y1, x2, y2, …] - Numpy array with shape (N, 2) or (N, 1, 2)

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> points = [[10, 10], [50, 20], [90, 10], [90, 90]]
>>> # Draw open polylines
>>> img = cv3.polylines(img, points, color='red', t=2)
>>> # Draw closed polylines
>>> img = cv3.polylines(img, points, is_closed=True, color='blue')
cv3.draw.fill_poly(img, pts, rel=None, color=None, copy=False)[source]

Draw a filled polygon on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • pts (array-like) – Points defining the polygon. Can be a numpy array, list of lists, or tuple of tuples with shape (N, 2) where N is the number of points.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color to fill the polygon (default: opt.COLOR).

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the filled polygon drawn on it.

Return type:

numpy.ndarray

Note

Points can be specified in various formats: - List of [x, y] coordinates: [[x1, y1], [x2, y2], …] - Tuple of (x, y) coordinates: ((x1, y1), (x2, y2), …) - Flattened list: [x1, y1, x2, y2, …] - Numpy array with shape (N, 2) or (N, 1, 2)

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> points = [[10, 10], [50, 20], [90, 10], [90, 90]]
>>> # Draw a filled polygon
>>> img = cv3.fill_poly(img, points, color='red')
cv3.draw.circle(img, x0, y0, r, rel=None, r_mode='min', color=None, t=None, line_type=None, fill=None, copy=False)[source]

Draw a circle on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • x0 (int or float) – X-coordinate of the circle center.

  • y0 (int or float) – Y-coordinate of the circle center.

  • r (int or float) – Radius of the circle.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • r_mode (str, optional) – Mode for relative radius calculation. One of ‘w’, ‘h’, ‘min’, ‘max’, ‘diag’. Only used when rel=True for the radius. Defaults to ‘min’. - ‘w’: Relative to image width - ‘h’: Relative to image height - ‘min’: Relative to minimum of width and height - ‘max’: Relative to maximum of width and height - ‘diag’: Relative to image diagonal

  • color – Color of the circle (default: opt.COLOR).

  • t – Thickness of the circle line. Use -1 or cv2.FILLED for filled circle (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • fill (bool, optional) – Whether to fill the circle. If True, draws a filled circle regardless of thickness. If False, draws an outlined circle. If None, uses the thickness parameter to determine fill behavior. Defaults to None.

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the circle drawn on it.

Return type:

numpy.ndarray

Note

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

To draw a filled circle, you can either: - Use t=-1 or set the thickness parameter to -1 - Use fill=True

When fill=True, the circle is filled regardless of the thickness value. When fill=False, the circle is outlined with the specified thickness. When fill=None (default), the circle is filled if t=-1, otherwise outlined.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw a circle with outline
>>> img = cv3.circle(img, 50, 50, 30, color='red', t=2)
>>> # Draw a filled circle using fill parameter
>>> img = cv3.circle(img, 80, 80, 15, color='blue', fill=True)
>>> # Draw a filled circle using thickness parameter
>>> img = cv3.circle(img, 20, 20, 10, color='green', t=-1)
>>> # Draw a circle with relative radius based on image width
>>> img = cv3.circle(img, 0.5, 0.5, 0.2, rel=True, r_mode='w', color='yellow')
cv3.draw.point(img, x0, y0, r=None, rel=None, r_mode='min', color=None, copy=False)[source]

Draw a point (filled circle) on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • x0 (int or float) – X-coordinate of the point center.

  • y0 (int or float) – Y-coordinate of the point center.

  • r (int or float, optional) – Radius of the point. Defaults to opt.PT_RADIUS.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • r_mode (str, optional) – Mode for relative radius calculation. One of ‘w’, ‘h’, ‘min’, ‘max’, ‘diag’. Only used when rel=True for the radius. Defaults to ‘min’. - ‘w’: Relative to image width - ‘h’: Relative to image height - ‘min’: Relative to minimum of width and height - ‘max’: Relative to maximum of width and height - ‘diag’: Relative to image diagonal

  • color – Color of the point (default: opt.COLOR).

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the point drawn on it.

Return type:

numpy.ndarray

Note

This function draws a filled circle (point) on the image. The thickness parameter ‘t’ is not used for points as they are always filled.

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw a point
>>> img = cv3.point(img, 50, 50, color='red')
>>> # Draw a point with custom radius
>>> img = cv3.point(img, 80, 80, r=5, color='blue')
>>> # Draw a point with relative radius based on image width
>>> img = cv3.point(img, 0.5, 0.5, r=0.1, rel=True, r_mode='w', color='green')
cv3.draw.points(img: array, pts: List[List], *args, **kwargs) → array[source]

Draw multiple points on an image. See point() for more details.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • pts (List[List]) – List of points, where each point is a list of parameters to pass to the point function.

  • *args – Additional arguments to pass to the point() function.

  • **kwargs – Additional keyword arguments to pass to the point() function.

Returns:

Image with all points drawn on it.

Return type:

numpy.ndarray

Note

Each point in the pts list should contain the parameters needed for the point function (x0, y0, r, etc.).

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw multiple points
>>> points = [
...     [10, 10],
...     [40, 40],
...     [70, 70]
... ]
>>> img = cv3.points(img, points, color='red')
>>> # Draw multiple points with relative radius based on image width
>>> points = [
...     [0.2, 0.2],
...     [0.5, 0.5],
...     [0.8, 0.8]
... ]
>>> img = cv3.points(img, points, r=0.1, rel=True, r_mode='w', color='blue')
cv3.draw.line(img, x0, y0, x1, y1, rel=None, color=None, t=None, line_type=None, copy=False)[source]

Draw a line on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • x0 (int or float) – X-coordinate of the first point.

  • y0 (int or float) – Y-coordinate of the first point.

  • x1 (int or float) – X-coordinate of the second point.

  • y1 (int or float) – Y-coordinate of the second point.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the line (default: opt.COLOR).

  • t – Thickness of the line (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the line drawn on it.

Return type:

numpy.ndarray

Note

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw a line
>>> img = cv3.line(img, 10, 10, 90, 90, color='red', t=2)
>>> # Draw a line using relative coordinates
>>> img = cv3.line(img, 0.2, 0.2, 0.8, 0.8, rel=True, color='blue')
cv3.draw.hline(img, y, rel=None, color=None, t=None, line_type=None, copy=False)[source]

Draw a horizontal line on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • y (int or float) – Y-coordinate of the horizontal line.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the line (default: opt.COLOR).

  • t – Thickness of the line (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the horizontal line drawn on it.

Return type:

numpy.ndarray

Note

Relative coordinates are in the range [0, 1] where 0 is the top and 1 is the bottom of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw a horizontal line in the middle
>>> img = cv3.hline(img, 50, color='red', t=2)
>>> # Draw a horizontal line using relative coordinates
>>> img = cv3.hline(img, 0.75, rel=True, color='blue')
cv3.draw.vline(img, x, rel=None, color=None, t=None, line_type=None, copy=False)[source]

Draw a vertical line on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • x (int or float) – X-coordinate of the vertical line.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the line (default: opt.COLOR).

  • t – Thickness of the line (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the vertical line drawn on it.

Return type:

numpy.ndarray

Note

Relative coordinates are in the range [0, 1] where 0 is the left and 1 is the right of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw a vertical line in the middle
>>> img = cv3.vline(img, 50, color='red', t=2)
>>> # Draw a vertical line using relative coordinates
>>> img = cv3.vline(img, 0.75, rel=True, color='blue')
cv3.draw.text(img, text_str, x=0.5, y=0.5, font=None, scale=None, flip=False, rel=None, color=None, t=None, line_type=None, copy=False)[source]

Draw text on an image.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • text_str (str) – Text string to be drawn.

  • x (int or float, optional) – X-coordinate of the bottom-left corner of the text. Defaults to 0.5 (center).

  • y (int or float, optional) – Y-coordinate of the bottom-left corner of the text. Defaults to 0.5 (center).

  • font (int or str, optional) – Font type. Can be an OpenCV font flag or string. Available string options: ‘simplex’, ‘plain’, ‘duplex’, ‘complex’, ‘triplex’, ‘complex_small’, ‘script_simplex’, ‘script_complex’, ‘italic’. Defaults to opt.FONT.

  • scale (float, optional) – Font scale factor that is multiplied by the font-specific base size. Defaults to opt.SCALE.

  • flip (bool, optional) – If True, the text is rendered upside down. Defaults to False.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the text (default: opt.COLOR).

  • t – Thickness of the text strokes (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the text drawn on it.

Return type:

numpy.ndarray

Note

Relative coordinates are in the range [0, 1] where (0, 0) is the top-left and (1, 1) is the bottom-right of the image.

The default position (x=0.5, y=0.5) places the text near the center of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw text at the center
>>> img = cv3.text(img, 'Hello', color='red')
>>> # Draw text with custom position and font
>>> img = cv3.text(img, 'World', x=10, y=50, font='complex', scale=1.2, color='blue')
>>> # Draw flipped text
>>> img = cv3.text(img, 'Flipped', x=50, y=80, flip=True, color='green')
cv3.draw.putText(img, text_str, x=0.5, y=0.5, font=None, scale=None, flip=False, rel=None, color=None, t=None, line_type=None, copy=False)

Alias for text().

cv3.draw.rectangles(img: array, rects: List[List], *args, **kwargs) → array[source]

Draw multiple rectangles on an image. See rectangle() for more details.

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • rects (List[List]) – List of rectangles, where each rectangle is a list of parameters to pass to the rectangle function.

  • *args – Additional arguments to pass to the rectangle() function.

  • **kwargs – Additional keyword arguments to pass to the rectangle() function.

Returns:

Image with all rectangles drawn on it.

Return type:

numpy.ndarray

Note

Each rectangle in the rects list should contain the parameters needed for the rectangle function (x0, y0, x1, y1, etc.).

The coordinate modes are: - ‘xyxy’: Two corner points (x0, y0) and (x1, y1) - ‘xywh’: Top-left corner (x0, y0) and width (x1), height (y1) - ‘ccwh’: Center point (x0, y0) and width (x1), height (y1)

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

When fill=True, the rectangles are filled regardless of the thickness value. When fill=False, the rectangles are outlined with the specified thickness. When fill=None (default), the rectangles are filled if t=-1, otherwise outlined.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw multiple rectangles
>>> rectangles = [
...     [10, 10, 30, 30],
...     [40, 40, 60, 60],
...     [70, 70, 90, 90]
... ]
>>> img = cv3.rectangles(img, rectangles, color='red', t=2)
>>> # Draw multiple filled rectangles
>>> filled_rectangles = [
...     [15, 15, 35, 35],
...     [45, 45, 65, 65]
... ]
>>> img = cv3.rectangles(img, filled_rectangles, color='blue', fill=True)
cv3.draw.rect(img, x0, y0, x1, y1, mode='xyxy', rel=None, color=None, t=None, line_type=None, fill=None, copy=False)

Alias for rectangles().

cv3.draw.rects(img: array, rects: List[List], *args, **kwargs) → array

Alias for rectangles().

cv3.draw.arrow(img, x0, y0, x1, y1, rel=None, color=None, t=None, line_type=None, tip_length=None, copy=False)[source]

Draw an arrowed line on an image.

This is an experimental function. To use it, set experimental mode with cv3.opt.set_exp().

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • x0 (int or float) – X-coordinate of the starting point.

  • y0 (int or float) – Y-coordinate of the starting point.

  • x1 (int or float) – X-coordinate of the ending point.

  • y1 (int or float) – Y-coordinate of the ending point.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the arrow (default: opt.COLOR).

  • t – Thickness of the arrow (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • tip_length (float, optional) – The length of the arrow tip in relation to the arrow length. Defaults to 0.1.

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the arrow drawn on it.

Return type:

numpy.ndarray

Note

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw an arrow
>>> img = cv3.arrow(img, 10, 10, 90, 90, color='red', t=2)
>>> # Draw an arrow with custom tip length
>>> img = cv3.arrow(img, 20, 20, 80, 80, color='blue', tip_length=0.2)
cv3.draw.ellipse(img, x, y, axes_x, axes_y, angle=0, start_angle=0, end_angle=360, rel=None, color=None, t=None, line_type=None, fill=None, copy=False)[source]

Draw an ellipse on an image.

This is an experimental function. To use it, set experimental mode with cv3.opt.set_exp().

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • x (int or float) – X-coordinate of the ellipse center.

  • y (int or float) – Y-coordinate of the ellipse center.

  • axes_x (int or float) – Half of the size of the ellipse main axis x.

  • axes_y (int or float) – Half of the size of the ellipse main axis y.

  • angle (float, optional) – Ellipse rotation angle in degrees. Defaults to 0.

  • start_angle (float, optional) – Starting angle of the elliptic arc in degrees. Defaults to 0.

  • end_angle (float, optional) – Ending angle of the elliptic arc in degrees. Defaults to 360.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the ellipse (default: opt.COLOR).

  • t – Thickness of the ellipse line. Use -1 or cv2.FILLED for filled ellipse (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • fill (bool, optional) – Whether to fill the ellipse. If True, draws a filled ellipse regardless of thickness. If False, draws an outlined ellipse. If None, uses the thickness parameter to determine fill behavior. Defaults to None.

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the ellipse drawn on it.

Return type:

numpy.ndarray

Note

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

To draw a filled ellipse, you can either: - Use t=-1 or set the thickness parameter to -1 - Use fill=True

When fill=True, the ellipse is filled regardless of the thickness value. When fill=False, the ellipse is outlined with the specified thickness. When fill=None (default), the ellipse is filled if t=-1, otherwise outlined.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw an ellipse with outline
>>> img = cv3.ellipse(img, 50, 50, 30, 20, color='red', t=2)
>>> # Draw a filled ellipse using fill parameter
>>> img = cv3.ellipse(img, 80, 80, 15, 10, color='blue', fill=True)
>>> # Draw a filled ellipse using thickness parameter
>>> img = cv3.ellipse(img, 20, 20, 10, 5, color='green', t=-1)
cv3.draw.marker(img, x, y, marker_type=None, marker_size=None, rel=None, color=None, t=None, line_type=None, copy=False)[source]

Draw a marker on an image.

This is an experimental function. To use it, set experimental mode with cv3.opt.set_exp().

Parameters:

  • img (numpy.ndarray) – Input image to draw on.

  • x (int or float) – X-coordinate of the marker position.

  • y (int or float) – Y-coordinate of the marker position.

  • marker_type (int or str, optional) – The specific type of marker you want to use. Can be one of: ‘cross’, ‘tilted_cross’, ‘star’, ‘diamond’, ‘square’, ‘triangle_up’, ‘triangle_down’. Defaults to cv2.MARKER_CROSS.

  • marker_size (int, optional) – The length of the marker axis. Defaults to 20.

  • rel (bool, optional) – Whether to use relative coordinates. Defaults to None.

  • color – Color of the marker (default: opt.COLOR).

  • t – Thickness of the marker lines (default: opt.THICKNESS).

  • line_type – Type of line for drawing (default: opt.LINE_TYPE).

  • copy (bool) – Whether to copy the image before drawing (default: False).

Returns:

Image with the marker drawn on it.

Return type:

numpy.ndarray

Note

Relative coordinates are in the range [0, 1] where 0 is the top/left and 1 is the bottom/right of the image.

Example

>>> import cv3
>>> img = cv3.zeros(100, 100, 3)
>>> # Draw a cross marker
>>> img = cv3.marker(img, 50, 50, color='red', t=2)
>>> # Draw a star marker with custom size
>>> img = cv3.marker(img, 80, 80, marker_type='star', marker_size=30, color='blue')
cv3.draw.getTextSize(text, font=None, scale=None, t=None)[source]

Calculate the width and height of a text string.

This is an experimental function. To use it, set experimental mode with cv3.opt.set_exp().

Parameters:

  • text (str) – Input text string.

  • font (int or str, optional) – Font type. Can be an OpenCV font flag or string. Available string options: ‘simplex’, ‘plain’, ‘duplex’, ‘complex’, ‘triplex’, ‘complex_small’, ‘script_simplex’, ‘script_complex’, ‘italic’. Defaults to opt.FONT.

  • scale (float, optional) – Font scale factor that is multiplied by the font-specific base size. Defaults to opt.SCALE.

  • t (int, optional) – Thickness of the lines used to draw a text. Defaults to opt.THICKNESS.

Returns:

A tuple containing:

  • Size: The size of a box that contains the specified text.

  • baseline (int): y-coordinate of the baseline relative to the bottom-most text point.

Return type:

tuple

Example

>>> import cv3
>>> # Get text size
>>> text_size, baseline = cv3.getTextSize('Hello World', font='simplex', scale=1.2, t=2)
>>> print(f"Text size: {text_size}, Baseline: {baseline}")
cv3.draw.poly(img, pts, is_closed=False, rel=None, color=None, t=None, line_type=None, copy=False)

Alias for polylines().

cv3.draw.polygon(img, pts, is_closed=False, rel=None, color=None, t=None, line_type=None, copy=False)

Alias for polylines().

rectangle(img, x0, y0, x1, y1[, mode, rel, ...])

Draw a rectangle on an image.

polylines(img, pts[, is_closed, rel, color, ...])

Draw polylines on an image.

fill_poly(img, pts[, rel, color, copy])

Draw a filled polygon on an image.

circle(img, x0, y0, r[, rel, r_mode, color, ...])

Draw a circle on an image.

point(img, x0, y0[, r, rel, r_mode, color, copy])

Draw a point (filled circle) on an image.

points(img, pts, *args, **kwargs)

Draw multiple points on an image.

line(img, x0, y0, x1, y1[, rel, color, t, ...])

Draw a line on an image.

hline(img, y[, rel, color, t, line_type, copy])

Draw a horizontal line on an image.

vline(img, x[, rel, color, t, line_type, copy])

Draw a vertical line on an image.

text(img, text_str[, x, y, font, scale, ...])

Draw text on an image.

rectangles(img, rects, *args, **kwargs)

Draw multiple rectangles on an image.

arrow(img, x0, y0, x1, y1[, rel, color, t, ...])

Draw an arrowed line on an image.

ellipse(img, x, y, axes_x, axes_y[, angle, ...])

Draw an ellipse on an image.

marker(img, x, y[, marker_type, ...])

Draw a marker on an image.

getTextSize(text[, font, scale, t])

Calculate the width and height of a text string.

putText(img, text_str[, x, y, font, scale, ...])

Alias for text().