Canvas

Examples

Live example

Smiling face

import math

import flet as ft
import flet.canvas as cv


def main(page: ft.Page):
    stroke_paint = ft.Paint(stroke_width=2, style=ft.PaintingStyle.STROKE)
    fill_paint = ft.Paint(style=ft.PaintingStyle.FILL)

    page.add(
        cv.Canvas(
            width=float("inf"),
            expand=True,
            shapes=[
                cv.Circle(100, 100, 50, stroke_paint),
                cv.Circle(80, 90, 10, stroke_paint),
                cv.Circle(84, 87, 5, fill_paint),
                cv.Circle(120, 90, 10, stroke_paint),
                cv.Circle(124, 87, 5, fill_paint),
                cv.Arc(70, 95, 60, 40, 0, math.pi, paint=stroke_paint),
            ],
        )
    )


ft.run(main)

Flet logo

import flet as ft
import flet.canvas as cv


def main(page: ft.Page):
    page.theme_mode = ft.ThemeMode.LIGHT

    page.add(
        cv.Canvas(
            width=float("inf"),
            expand=True,
            shapes=[
                cv.Path(
                    elements=[
                        cv.Path.MoveTo(25, 125),
                        cv.Path.QuadraticTo(50, 25, 135, 35, 0.35),
                        cv.Path.QuadraticTo(75, 115, 135, 215, 0.6),
                        cv.Path.QuadraticTo(50, 225, 25, 125, 0.35),
                    ],
                    paint=ft.Paint(
                        stroke_width=2,
                        style=ft.PaintingStyle.FILL,
                        color=ft.Colors.PINK_400,
                    ),
                ),
                cv.Path(
                    elements=[
                        cv.Path.MoveTo(85, 125),
                        cv.Path.QuadraticTo(120, 85, 165, 75, 0.5),
                        cv.Path.QuadraticTo(120, 115, 165, 175, 0.3),
                        cv.Path.QuadraticTo(120, 165, 85, 125, 0.5),
                    ],
                    paint=ft.Paint(
                        stroke_width=2,
                        style=ft.PaintingStyle.FILL,
                        color=ft.Colors.with_opacity(0.5, ft.Colors.BLUE_400),
                    ),
                ),
            ],
        )
    )


ft.run(main)

Triangles

import flet as ft
import flet.canvas as cv


def main(page: ft.Page):
    page.add(
        cv.Canvas(
            width=float("inf"),
            expand=True,
            shapes=[
                cv.Path(
                    paint=ft.Paint(style=ft.PaintingStyle.FILL),
                    elements=[
                        cv.Path.MoveTo(25, 25),
                        cv.Path.LineTo(105, 25),
                        cv.Path.LineTo(25, 105),
                    ],
                ),
                cv.Path(
                    paint=ft.Paint(stroke_width=2, style=ft.PaintingStyle.STROKE),
                    elements=[
                        cv.Path.MoveTo(125, 125),
                        cv.Path.LineTo(125, 45),
                        cv.Path.LineTo(45, 125),
                        cv.Path.Close(),
                    ],
                ),
            ],
        )
    )


ft.run(main)

Bezier curves

import flet as ft
import flet.canvas as cv


def main(page: ft.Page):
    cp = cv.Canvas(
        width=float("inf"),
        expand=True,
        shapes=[
            cv.Path(
                paint=ft.Paint(stroke_width=2, style=ft.PaintingStyle.STROKE),
                elements=[
                    cv.Path.MoveTo(75, 25),
                    cv.Path.QuadraticTo(25, 25, 25, 62.5),
                    cv.Path.QuadraticTo(25, 100, 50, 100),
                    cv.Path.QuadraticTo(50, 120, 30, 125),
                    cv.Path.QuadraticTo(60, 120, 65, 100),
                    cv.Path.QuadraticTo(125, 100, 125, 62.5),
                    cv.Path.QuadraticTo(125, 25, 75, 25),
                ],
            ),
            cv.Path(
                elements=[
                    cv.Path.SubPath(
                        x=100,
                        y=100,
                        elements=[
                            cv.Path.MoveTo(75, 40),
                            cv.Path.CubicTo(75, 37, 70, 25, 50, 25),
                            cv.Path.CubicTo(20, 25, 20, 62.5, 20, 62.5),
                            cv.Path.CubicTo(20, 80, 40, 102, 75, 120),
                            cv.Path.CubicTo(110, 102, 130, 80, 130, 62.5),
                            cv.Path.CubicTo(130, 62.5, 130, 25, 100, 25),
                            cv.Path.CubicTo(85, 25, 75, 37, 75, 40),
                        ],
                    )
                ],
                paint=ft.Paint(
                    style=ft.PaintingStyle.FILL,
                    gradient=ft.PaintRadialGradient(
                        center=ft.Offset(150, 150),
                        radius=50,
                        colors=[ft.Colors.PINK_100, ft.Colors.PINK],
                    ),
                ),
            ),
        ],
    )

    page.add(cp)


ft.run(main)

Text

import math

import flet as ft
import flet.canvas as cv


def main(page: ft.Page):
    page.add(
        cv.Canvas(
            width=float("inf"),
            expand=True,
            shapes=[
                cv.Text(x=0, y=0, value="Just a text"),
                cv.Circle(x=200, y=100, radius=2, paint=ft.Paint(color=ft.Colors.RED)),
                cv.Text(
                    x=200,
                    y=100,
                    style=ft.TextStyle(weight=ft.FontWeight.BOLD, size=30),
                    alignment=ft.Alignment.TOP_CENTER,
                    rotate=math.pi * 0.15,
                    value="Rotated",
                    spans=[
                        ft.TextSpan(
                            text="around top_center",
                            style=ft.TextStyle(
                                italic=True, color=ft.Colors.GREEN, size=20
                            ),
                        )
                    ],
                ),
                cv.Circle(x=400, y=100, radius=2, paint=ft.Paint(color=ft.Colors.RED)),
                cv.Text(
                    x=400,
                    y=100,
                    value="Rotated around top_left",
                    style=ft.TextStyle(size=20),
                    alignment=ft.Alignment.TOP_LEFT,
                    rotate=math.pi * -0.15,
                ),
                cv.Circle(x=600, y=200, radius=2, paint=ft.Paint(color=ft.Colors.RED)),
                cv.Text(
                    x=600,
                    y=200,
                    value="Rotated around center",
                    style=ft.TextStyle(size=20),
                    alignment=ft.Alignment.CENTER,
                    rotate=math.pi / 2,
                ),
                cv.Text(
                    x=300,
                    y=400,
                    value="Limited to max_width and right-aligned.\nLorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.",
                    text_align=ft.TextAlign.RIGHT,
                    max_width=400,
                ),
                cv.Text(
                    x=200,
                    y=200,
                    value="WOW!",
                    style=ft.TextStyle(
                        weight=ft.FontWeight.BOLD,
                        size=100,
                        foreground=ft.Paint(
                            color=ft.Colors.PINK,
                            stroke_width=6,
                            style=ft.PaintingStyle.STROKE,
                            stroke_join=ft.StrokeJoin.ROUND,
                            stroke_cap=ft.StrokeCap.ROUND,
                        ),
                    ),
                ),
                cv.Text(
                    x=200,
                    y=200,
                    value="WOW!",
                    style=ft.TextStyle(
                        weight=ft.FontWeight.BOLD,
                        size=100,
                        foreground=ft.Paint(
                            gradient=ft.PaintLinearGradient(
                                begin=(200, 200),
                                end=(300, 300),
                                colors=[ft.Colors.YELLOW, ft.Colors.RED],
                            ),
                            stroke_join=ft.StrokeJoin.ROUND,
                            stroke_cap=ft.StrokeCap.ROUND,
                        ),
                    ),
                ),
            ],
        )
    )


ft.run(main)

Free-hand drawing with brush

import flet as ft
import flet.canvas as cv


class State:
    x: float
    y: float


state = State()


def main(page: ft.Page):
    page.title = "Canvas Example"

    def handle_pan_start(e: ft.DragStartEvent):
        state.x = e.local_x
        state.y = e.local_y

    def handle_pan_update(e: ft.DragUpdateEvent):
        canvas.shapes.append(
            cv.Line(
                x1=state.x,
                y1=state.y,
                x2=e.local_x,
                y2=e.local_y,
                paint=ft.Paint(stroke_width=3),
            )
        )
        canvas.update()
        state.x = e.local_x
        state.y = e.local_y

    canvas = cv.Canvas(
        expand=False,
        shapes=[
            cv.Fill(
                ft.Paint(
                    gradient=ft.PaintLinearGradient(
                        begin=(0, 0),
                        end=(600, 600),
                        colors=[ft.Colors.CYAN_50, ft.Colors.GREY],
                    )
                )
            ),
        ],
        content=ft.GestureDetector(
            on_pan_start=handle_pan_start,
            on_pan_update=handle_pan_update,
            drag_interval=10,
        ),
    )

    page.add(
        ft.Container(
            content=canvas,
            border_radius=5,
            width=float("inf"),
            expand=True,
        )
    )


ft.run(main)

Canvas

Bases: ConstrainedControl

Canvas is a control for drawing arbitrary graphics using a set of primitives or "shapes" such as line, arc, path and text.

animate_offset

animate_offset: AnimationValue | None = None

Enables implicit animation of the offset property.

More information here.

animate_opacity

animate_opacity: AnimationValue | None = None

Enables implicit animation of the opacity property.

More information here.

animate_position

animate_position: AnimationValue | None = None

Enables implicit animation of the positioning properties (left, right, top and bottom).

More information here.

animate_rotation

animate_rotation: AnimationValue | None = None

Enables implicit animation of the rotate property.

More information here.

animate_scale

animate_scale: AnimationValue | None = None

Enables implicit animation of the scale property.

More information here.

animate_size

animate_size: AnimationValue | None = None

TBD

aspect_ratio

aspect_ratio: Number | None = None

TBD

badge

badge: BadgeValue | None = None

A badge to show on top of this control.

bottom

bottom: Number | None = None

The distance that the child's bottom edge is inset from the bottom of the stack.

Note

Effective only if this control is a descendant of one of the following: Stack control, Page.overlay list.

col

col: ResponsiveNumber = 12

If a parent of this control is a ResponsiveRow, this property is used to determine how many virtual columns of a screen this control will span.

Can be a number or a dictionary configured to have a different value for specific breakpoints, for example col={"sm": 6}.

This control spans the 12 virtual columns by default.

Dimensions

Breakpoint	Dimension
xs	<576px
sm	≥576px
md	≥768px
lg	≥992px
xl	≥1200px
xxl	≥1400px

content

content: Control | None = None

The content of this canvas.

data

data: Any = skip_field()

Arbitrary data of any type.

disabled

disabled: bool = False

Every control has disabled property which is False by default - control and all its children are enabled.

Note

The value of this property will be propagated down to all children controls recursively.

Example

For example, if you have a form with multiple entry controls you can disable them all together by disabling container:

ft.Column(
    disabled = True,
    controls=[
        ft.TextField(),
        ft.TextField()
    ]
)

expand

expand: bool | int | None = None

Specifies whether/how this control should expand to fill available space in its parent layout.

More information here.

Note

Has effect only if the direct parent of this control is one of the following controls, or their subclasses: Column, Row, View, Page.

expand_loose

expand_loose: bool = False

Allows the control to expand along the main axis if space is available, but does not require it to fill all available space.

More information here.

Note

If expand_loose is True, it will have effect only if:

• expand is not None and
• the direct parent of this control is one of the following controls, or their subclasses: Column, Row, View, Page.

height

height: Number | None = None

Imposed Control height in virtual pixels.

key

key: (
    str | int | float | bool | ValueKey | ScrollKey | None
) = None

left

left: Number | None = None

The distance that the child's left edge is inset from the left of the stack.

Note

Effective only if this control is a descendant of one of the following: Stack control, Page.overlay list.

offset

offset: OffsetValue | None = None

Applies a translation transformation before painting the control.

The translation is expressed as an Offset scaled to the control's size. So, Offset(x=0.25, y=0), for example, will result in a horizontal translation of one quarter the width of this control.

Example

The following example displays container at 0, 0 top left corner of a stack as transform applies -1 * 100, -1 * 100 (offset * control's size) horizontal and vertical translations to the control:

import flet as ft

def main(page: ft.Page):
    page.add(
        ft.Stack(
            width=1000,
            height=1000,
            controls=[
                ft.Container(
                    bgcolor="red",
                    width=100,
                    height=100,
                    left=100,
                    top=100,
                    offset=ft.Offset(-1, -1),
                )
            ],
        )
    )

ft.run(main)

on_animation_end

on_animation_end: (
    ControlEventHandler[ConstrainedControl] | None
) = None

Called when animation completes.

Can be used to chain multiple animations.

The data property of the event handler argument contains the name of the animation.

More information here.

on_resize

on_resize: EventHandler[CanvasResizeEvent] | None = None

Called when the size of this canvas has changed.

opacity

opacity: Number = 1.0

Defines the transparency of the control.

Value ranges from 0.0 (completely transparent) to 1.0 (completely opaque without any transparency).

page

page: Page | PageView | None

The page (of type Page or PageView) to which this control belongs to.

parent

parent: BaseControl | None

The direct ancestor(parent) of this control.

It defaults to None and will only have a value when this control is mounted (added to the page tree).

The Page control (which is the root of the tree) is an exception - it always has parent=None.

resize_interval

resize_interval: Number = 10

Sampling interval in milliseconds for on_resize event.

Setting to 0 calls on_resize immediately on every change.

right

right: Number | None = None

The distance that the child's right edge is inset from the right of the stack.

Note

Effective only if this control is a descendant of one of the following: Stack control, Page.overlay list.

rotate

rotate: RotateValue | None = None

Transforms this control using a rotation around its center.

The value of rotate property could be one of the following types:

• number - a rotation in clockwise radians. Full circle 360° is math.pi * 2 radians, 90° is pi / 2, 45° is pi / 4, etc.
• Rotate - allows to specify rotation angle as well as alignment - the location of rotation center.

Example

For example:

ft.Image(
    src="https://picsum.photos/100/100",
    width=100,
    height=100,
    border_radius=5,
    rotate=Rotate(angle=0.25 * pi, alignment=ft.Alignment.CENTER_LEFT)
)

rtl

rtl: bool = False

Whether the text direction of the control should be right-to-left (RTL).

scale

scale: ScaleValue | None = None

Scales this control along the 2D plane. Default scale factor is 1.0, meaning no-scale.

Setting this property to 0.5, for example, makes this control twice smaller, while 2.0 makes it twice larger.

Different scale multipliers can be specified for x and y axis, by setting Control.scale property to an instance of Scale class. Either scale or scale_x and scale_y could be specified, but not all of them.

Example

ft.Image(
    src="https://picsum.photos/100/100",
    width=100,
    height=100,
    border_radius=5,
    scale=ft.Scale(scale_x=2, scale_y=0.5)
)

shapes

shapes: list[Shape] = field(default_factory=list)

A list of shapes to draw on this canvas.

tooltip

tooltip: TooltipValue | None = None

The tooltip ot show when this control is hovered over.

top

top: Number | None = None

The distance that the child's top edge is inset from the top of the stack.

Note

Effective only if this control is a descendant of one of the following: Stack control, Page.overlay list.

visible

visible: bool = True

Every control has visible property which is True by default - control is rendered on the page. Setting visible to False completely prevents control (and all its children if any) from rendering on a page canvas. Hidden controls cannot be focused or selected with a keyboard or mouse and they do not emit any events.

width

width: Number | None = None

Imposed Control width in virtual pixels.

before_event

before_event(e: ControlEvent)

before_update

before_update()

clean

clean() -> None

did_mount

did_mount()

init

init()

is_isolated

is_isolated()

update

update() -> None

will_unmount

will_unmount()