Interface ICanvas

Common interface for all output formats to draw the QR bill.

The coordinate system has its origin in the bottom left corner. The y-axis extends from the bottom to the top.

The graphics model is similar to the one used by PDF, in particular with regards to the orientation of the y axis, the concept of a current path, and using the baseline for positioning text.

Instance of this class are expected to use a single font family for the QR bill (regular and bold font weight).

Inherited Members

IDisposable.Dispose()

Namespace: Codecrete.SwissQRBill.Generator.Canvas

Assembly: Codecrete.SwissQRBill.Core.dll

Syntax

public interface ICanvas : IDisposable

Methods

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AddRectangle(double, double, double, double)

Adds a rectangle to the open path.

Declaration

void AddRectangle(double x, double y, double width, double height)

Parameters

Type	Name	Description
double	x	The rectangle's left position (in mm).
double	y	The rectangle's top position (in mm).
double	width	The rectangle's width (in mm).
double	height	The rectangle's height (in mm).

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Ascender(int)

Gets the distance between the baseline and the top of the tallest letter.

Declaration

double Ascender(int fontSize)

Parameters

Type	Name	Description
int	fontSize	The font size (in pt).

Returns

Type	Description
double	The distance (in mm).

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CloseSubpath()

Closes the current subpath. The next path operation will implicitly open a new subpath.

Declaration

void CloseSubpath()

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CubicCurveTo(double, double, double, double, double, double)

Adds a cubic Beziér curve to the open path going from the previous point to the specified position. Two control points determine the curve.

Declaration

void CubicCurveTo(double x1, double y1, double x2, double y2, double x, double y)

Parameters

Type	Name	Description
double	x1	The x-coordinate of first control point.
double	y1	The y-coordinate of first control point.
double	x2	The x-coordinate of second control point.
double	y2	The y-coordinate of second control point.
double	x	The x-coordinate of position.
double	y	The y-coordinate of position.

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Descender(int)

Gets the distance between the baseline and the bottom of the letter extending the farthest below the baseline.

Declaration

double Descender(int fontSize)

Parameters

Type	Name	Description
int	fontSize	The font size (in pt).

Returns

Type	Description
double	The distance (in mm).

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FillPath(int, bool)

Fills the current path and discards it.

Declaration

void FillPath(int color, bool smoothing = true)

Parameters

Type	Name	Description
int	color	The fill color (expressed similar to HTML, e.g. 0xffffff for white).
bool	smoothing	`true` for using smoothing techniques such as antialiasing, `false` otherwise

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LineHeight(int)

Gets the distance between the baselines of two consecutive text lines.

Declaration

double LineHeight(int fontSize)

Parameters

Type	Name	Description
int	fontSize	The font size (in pt).

Returns

Type	Description
double	The distance (in mm).

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LineTo(double, double)

Adds a line segment to the open path from the previous point to the specified position.

Declaration

void LineTo(double x, double y)

Parameters

Type	Name	Description
double	x	The x-coordinate of position.
double	y	The y-coordinate of position.

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MoveTo(double, double)

Moves the current point of the open path to the specified position.

Declaration

void MoveTo(double x, double y)

Parameters

Type	Name	Description
double	x	The x-coordinate of position.
double	y	The y-coordinate of position.

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PutText(string, double, double, int, bool)

Draws text to the canvas.

The text position refers to the left most point on the text's baseline.

Declaration

void PutText(string text, double x, double y, int fontSize, bool isBold)

Parameters

Type	Name	Description
string	text	The text to draw.
double	x	The x position of the text's start (in mm).
double	y	The y position of the text's top (in mm).
int	fontSize	The font size (in pt).
bool	isBold	Flag indicating if the text is in bold or regular weight.

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PutTextLines(string[], double, double, int, double)

Adds several lines of text to the graphics.

The text position refers to the left most point on the baseline of the first text line. Additional lines then follow below.

Declaration

void PutTextLines(string[] lines, double x, double y, int fontSize, double leading)

Parameters

Type	Name	Description
string[]	lines	The text lines to draw.
double	x	The x position of the text's start (in mm).
double	y	The y position of the text's top (in mm).
int	fontSize	The font size (in pt).
double	leading	The amount of additional vertical space between text lines (in mm).

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SetTransformation(double, double, double, double, double)

Sets a translation, rotation and scaling for the subsequent operations.

Before a new translation is applied, the coordinate system is reset to it's original state.

The transformations are applied in the order translation, rotation, scaling.

Declaration

void SetTransformation(double translateX, double translateY, double rotate, double scaleX, double scaleY)

Parameters

Type	Name	Description
double	translateX	The translation in x direction (in mm).
double	translateY	The translation in y direction (in mm).
double	rotate	The rotation angle, in radians.
double	scaleX	The scale factor in x direction (1.0 = no scaling).
double	scaleY	The scale factor in y direction (1.0 = no scaling).

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SplitLines(string, double, int)

Splits the text into lines.

The text is split such that no line is wider the specified maximum width. If possible, the text is split at whitespace characters. If a word is wider than the specified maximum width, the word is split and put onto two or more lines. The text is always split at newlines.

Declaration

string[] SplitLines(string text, double maxLength, int fontSize)

Parameters

Type	Name	Description
string	text	The text to split into lines.
double	maxLength	The maximum line length (in pt).
int	fontSize	The font size (in pt).

Returns

Type	Description
string[]	The resulting array of text lines.

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StartPath()

Starts a path that can be filled or stroked.

Declaration

void StartPath()

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StrokePath(double, int, LineStyle, bool)

Strokes the current path and discards it.

Declaration

void StrokePath(double strokeWidth, int color, LineStyle lineStyle = LineStyle.Solid, bool smoothing = true)

Parameters

Type	Name	Description
double	strokeWidth	The stroke width (in pt).
int	color	The stroke color (expressed similar to HTML, e.g. 0xffffff for white).
LineStyle	lineStyle	The line style
bool	smoothing	`true` for using smoothing techniques such as antialiasing, `false` otherwise

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TextWidth(string, int, bool)

Measures the width of the specified text for the specified font size.

Declaration

double TextWidth(string text, int fontSize, bool isBold)

Parameters

Type	Name	Description
string	text	The text to measure.
int	fontSize	The text's font size (in pt).
bool	isBold	Flag indicating if the text is in bold or regular weight.

Returns

Type	Description
double	The measured width (in mm).

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ToByteArray()

Returns the result as a byte array.

Declaration

byte[] ToByteArray()

Returns

Type	Description
byte[]	The result.