#[repr(transparent)]
pub struct Matrix { /* private fields */ }
Expand description

A Matrix specifies a transformation between user-space and device coordinates.

The transformation is given by

x_device = x_user * matrix->xx + y_user * matrix->xy + matrix->x0;
y_device = x_user * matrix->yx + y_user * matrix->yy + matrix->y0;

Implementations

Changes the transformation represented by @self to be the transformation given by first applying transformation given by @new_matrix then applying the original transformation.

new_matrix

a Matrix

Returns the scale factor of a matrix on the height of the font.

That is, the scale factor in the direction perpendicular to the vector that the X coordinate is mapped to. If the scale in the X coordinate is needed as well, use font_scale_factors().

Returns

the scale factor of @self on the height of the font, or 1.0 if @self is None.

Calculates the scale factor of a matrix on the width and height of the font.

That is, @xscale is the scale factor in the direction of the X coordinate, and @yscale is the scale factor in the direction perpendicular to the vector that the X coordinate is mapped to.

Note that output numbers will always be non-negative.

Returns
xscale

output scale factor in the x direction

yscale

output scale factor perpendicular to the x direction

Available on crate feature v1_50 only.

Gets the slant ratio of a matrix.

For a simple shear matrix in the form:

1 λ
0 1

this is simply λ.

Returns

the slant ratio of @self

Changes the transformation represented by @self to be the transformation given by first rotating by @degrees degrees counter-clockwise then applying the original transformation.

degrees

degrees to rotate counter-clockwise

Changes the transformation represented by @self to be the transformation given by first scaling by @sx in the X direction and @sy in the Y direction then applying the original transformation.

scale_x

amount to scale by in X direction

scale_y

amount to scale by in Y direction

Transforms the distance vector (@dx,@dy) by @self.

This is similar to transform_point(), except that the translation components of the transformation are ignored. The calculation of the returned vector is as follows:

dx2 = dx1 * xx + dy1 * xy;
dy2 = dx1 * yx + dy1 * yy;

Affine transformations are position invariant, so the same vector always transforms to the same vector. If (@x1,@y1) transforms to (@x2,@y2) then (@x1+@dx1,@y1+@dy1) will transform to (@x1+@dx2,@y1+@dy2) for all values of @x1 and @x2.

dx

in/out X component of a distance vector

dy

in/out Y component of a distance vector

Transforms the point (@x, @y) by @self.

x

in/out X position

y

in/out Y position

Changes the transformation represented by @self to be the transformation given by first translating by (@tx, @ty) then applying the original transformation.

tx

amount to translate in the X direction

ty

amount to translate in the Y direction

First transforms the @rect using @self, then calculates the bounding box of the transformed rectangle.

This function is useful for example when you want to draw a rotated @PangoLayout to an image buffer, and want to know how large the image should be and how much you should shift the layout when rendering.

For better accuracy, you should use transform_rectangle() on original rectangle in Pango units and convert to pixels afterward using extents_to_pixels()’s first argument.

rect

in/out bounding box in device units

First transforms @rect using @self, then calculates the bounding box of the transformed rectangle.

This function is useful for example when you want to draw a rotated @PangoLayout to an image buffer, and want to know how large the image should be and how much you should shift the layout when rendering.

If you have a rectangle in device units (pixels), use transform_pixel_rectangle().

If you have the rectangle in Pango units and want to convert to transformed pixel bounding box, it is more accurate to transform it first (using this function) and pass the result to pango_extents_to_pixels(), first argument, for an inclusive rounded rectangle. However, there are valid reasons that you may want to convert to pixels first and then transform, for example when the transformed coordinates may overflow in Pango units (large matrix translation for example).

rect

in/out bounding box in Pango units

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Returns the type identifier of Self.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Ensures that the type has been registered with the type system.
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Returns a SendValue clone of self.
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.