gi-pango-1.0.22: Pango bindings
Copyright Will Thompson Iñaki García Etxebarria and Jonas Platte LGPL-2.1 Iñaki García Etxebarria None Haskell2010

GI.Pango.Structs.Matrix

Description

A structure specifying a transformation between user-space coordinates and device coordinates. The transformation is given by

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

Since: 1.6

Synopsis

# Exported types

newtype Matrix Source #

Memory-managed wrapper type.

Constructors

 Matrix (ManagedPtr Matrix)

#### Instances

Instances details
 Source # Instance detailsDefined in GI.Pango.Structs.Matrix Methods(==) :: Matrix -> Matrix -> Bool #(/=) :: Matrix -> Matrix -> Bool # Source # Instance detailsDefined in GI.Pango.Structs.Matrix Methods Source # Convert Matrix to and from GValue with toGValue and fromGValue. Instance detailsDefined in GI.Pango.Structs.Matrix Methods tag ~ 'AttrSet => Constructible Matrix tag Source # Instance detailsDefined in GI.Pango.Structs.Matrix Methodsnew :: MonadIO m => (ManagedPtr Matrix -> Matrix) -> [AttrOp Matrix tag] -> m Matrix #

Construct a Matrix struct initialized to zero.

A convenience alias for Nothing :: Maybe Matrix.

# Methods

## concat

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix -> Matrix newMatrix: a Matrix -> m ()

Changes the transformation represented by matrix to be the transformation given by first applying transformation given by newMatrix then applying the original transformation.

Since: 1.6

## copy

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix, may be Nothing -> m (Maybe Matrix) Returns: the newly allocated Matrix, which should be freed with matrixFree, or Nothing if matrix was Nothing.

Copies a Matrix.

Since: 1.6

## free

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix, may be Nothing -> m ()

Free a Matrix created with matrixCopy.

Since: 1.6

## getFontScaleFactor

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix, may be Nothing -> m Double Returns: the scale factor of matrix on the height of the font, or 1.0 if matrix is Nothing.

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 matrixGetFontScaleFactors.

Since: 1.12

## getFontScaleFactors

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix, or Nothing -> m (Double, Double)

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.

Since: 1.38

## rotate

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix -> Double degrees: degrees to rotate counter-clockwise -> m ()

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

Since: 1.6

## scale

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix -> Double scaleX: amount to scale by in X direction -> Double scaleY: amount to scale by in Y direction -> m ()

Changes the transformation represented by matrix 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.

Since: 1.6

## transformDistance

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix, or Nothing -> Double dx: in/out X component of a distance vector -> Double dy: in/out Y component of a distance vector -> m (Double, Double)

Transforms the distance vector (dx,dy) by matrix. This is similar to matrixTransformPoint except that the translation components of the transformation are ignored. The calculation of the returned vector is as follows:

<programlisting> dx2 = dx1 * xx + dy1 * xy; dy2 = dx1 * yx + dy1 * yy; </programlisting>

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.

Since: 1.16

## transformPixelRectangle

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix, or Nothing -> Maybe Rectangle rect: in/out bounding box in device units, or Nothing -> m ()

First transforms the rect using matrix, then calculates the bounding box of the transformed rectangle. The rectangle should be in device units (pixels).

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 matrixTransformRectangle on original rectangle in Pango units and convert to pixels afterward using extentsToPixels's first argument.

Since: 1.16

## transformPoint

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix, or Nothing -> Double x: in/out X position -> Double y: in/out Y position -> m (Double, Double)

Transforms the point (x, y) by matrix.

Since: 1.16

## translate

Arguments

 :: (HasCallStack, MonadIO m) => Matrix matrix: a Matrix -> Double tx: amount to translate in the X direction -> Double ty: amount to translate in the Y direction -> m ()

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

Since: 1.6

# Properties

## x0

x translation

getMatrixX0 :: MonadIO m => Matrix -> m Double Source #

Get the value of the “x0” field. When overloading is enabled, this is equivalent to

get matrix #x0


setMatrixX0 :: MonadIO m => Matrix -> Double -> m () Source #

Set the value of the “x0” field. When overloading is enabled, this is equivalent to

set matrix [ #x0 := value ]


## xx

1st component of the transformation matrix

getMatrixXx :: MonadIO m => Matrix -> m Double Source #

Get the value of the “xx” field. When overloading is enabled, this is equivalent to

get matrix #xx


setMatrixXx :: MonadIO m => Matrix -> Double -> m () Source #

Set the value of the “xx” field. When overloading is enabled, this is equivalent to

set matrix [ #xx := value ]


## xy

2nd component of the transformation matrix

getMatrixXy :: MonadIO m => Matrix -> m Double Source #

Get the value of the “xy” field. When overloading is enabled, this is equivalent to

get matrix #xy


setMatrixXy :: MonadIO m => Matrix -> Double -> m () Source #

Set the value of the “xy” field. When overloading is enabled, this is equivalent to

set matrix [ #xy := value ]


## y0

y translation

getMatrixY0 :: MonadIO m => Matrix -> m Double Source #

Get the value of the “y0” field. When overloading is enabled, this is equivalent to

get matrix #y0


setMatrixY0 :: MonadIO m => Matrix -> Double -> m () Source #

Set the value of the “y0” field. When overloading is enabled, this is equivalent to

set matrix [ #y0 := value ]


## yx

3rd component of the transformation matrix

getMatrixYx :: MonadIO m => Matrix -> m Double Source #

Get the value of the “yx” field. When overloading is enabled, this is equivalent to

get matrix #yx


setMatrixYx :: MonadIO m => Matrix -> Double -> m () Source #

Set the value of the “yx” field. When overloading is enabled, this is equivalent to

set matrix [ #yx := value ]


## yy

4th component of the transformation matrix

getMatrixYy :: MonadIO m => Matrix -> m Double Source #

Get the value of the “yy” field. When overloading is enabled, this is equivalent to

get matrix #yy


setMatrixYy :: MonadIO m => Matrix -> Double -> m () Source #

Set the value of the “yy” field. When overloading is enabled, this is equivalent to

set matrix [ #yy := value ]