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Java library for generating Swiss QR bills
//
// Swiss QR Bill Generator
// Copyright (c) 2017 Manuel Bleichenbacher
// Licensed under MIT License
// https://opensource.org/licenses/MIT
//
package net.codecrete.qrbill.canvas;
import java.io.Closeable;
import java.io.IOException;
/**
* 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).
*
*/
public interface Canvas extends Closeable {
/**
* Line style
*/
enum LineStyle {
/// Solid line
Solid,
/// Dashed line (dashes are about 4 times the line width long and apart)
Dashed,
/// Dotted line (dots are spaced 3 times the line width apart)
Dotted
}
/**
* 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.
*
*
* @param translateX translation in x direction (in mm)
* @param translateY translation in y direction (in mm)
* @param rotate rotation angle, in radians
* @param scaleX scale factor in x direction (1.0 = no scaling)
* @param scaleY scale factor in y direction (1.0 = no scaling)
* @throws IOException thrown if the graphics cannot be generated
*/
void setTransformation(double translateX, double translateY, double rotate, double scaleX, double scaleY) throws IOException;
/**
* Adds text to the graphics.
*
* The text position refers to the left most point on the text's baseline.
*
*
* @param text the text
* @param x x position of the text's start (in mm)
* @param y y position of the text's top (in mm)
* @param fontSize the font size (in pt)
* @param isBold indicates if the text is in bold or regular weight
* @throws IOException thrown if the graphics cannot be generated
*/
void putText(String text, double x, double y, int fontSize, boolean isBold) throws IOException;
/**
* 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.
*
*
* @param lines the text lines
* @param x x position of the text's start (in mm)
* @param y y position of the text's top (in mm)
* @param fontSize the font size (in pt)
* @param leading additional vertical space between text lines (in mm)
* @throws IOException thrown if the graphics cannot be generated
*/
void putTextLines(String[] lines, double x, double y, int fontSize, double leading) throws IOException;
/**
* Starts a path that can be filled or stroked
*
* @throws IOException thrown if the graphics cannot be generated
*/
void startPath() throws IOException;
/**
* Moves the current point of the open path to the specified position.
*
* @param x x-coordinate of position
* @param y y-coordinate of position
* @throws IOException thrown if the graphics cannot be generated
*/
void moveTo(double x, double y) throws IOException;
/**
* Adds a line segment to the open path from the previous point to the specified
* position.
*
* @param x x-coordinate of position
* @param y y-coordinate of position
* @throws IOException thrown if the graphics cannot be generated
*/
void lineTo(double x, double y) throws IOException;
/**
* Adds a cubic Beziér curve to the open path going from the previous point to the specified
* position. Two control points control the curve
*
* @param x1 x-coordinate of first control point
* @param y1 y-coordinate of first control point
* @param x2 x-coordinate of second control point
* @param y2 y-coordinate of second control point
* @param x x-coordinate of position
* @param y y-coordinate of position
* @throws IOException thrown if the graphics cannot be generated
*/
void cubicCurveTo(double x1, double y1, double x2, double y2, double x, double y) throws IOException;
/**
* Adds a rectangle to the path
*
* @param x the rectangle's left position (in mm)
* @param y the rectangle's top position (in mm)
* @param width the rectangle's width (in mm)
* @param height rectangle's height (in mm)
* @throws IOException thrown if the graphics cannot be generated
*/
void addRectangle(double x, double y, double width, double height) throws IOException;
/**
* Closes the current subpath
*
* @throws IOException thrown if the graphics cannot be generated
*/
void closeSubpath() throws IOException;
/**
* Fills the current path and ends it
*
* @param color the fill color (expressed similar to HTML, e.g. 0xffffff for
* white)
* @throws IOException thrown if the graphics cannot be generated
*/
void fillPath(int color) throws IOException;
/**
* Strokes the current path and ends it
*
* The path is stroked with a solid line.
*
*
* @param strokeWidth the stroke width (in pt)
* @param color the stroke color (expressed similar to HTML, e.g. 0xffffff
* for white)
* @throws IOException thrown if the graphics cannot be generated
*/
void strokePath(double strokeWidth, int color) throws IOException;
/**
* Strokes the current path and ends it
*
* @param strokeWidth the stroke width (in pt)
* @param color the stroke color (expressed similar to HTML, e.g. 0xffffff
* for white)
* @param lineStyle the line style
* @throws IOException thrown if the graphics cannot be generated
*/
default void strokePath(double strokeWidth, int color, LineStyle lineStyle) throws IOException {
strokePath(strokeWidth, color);
}
/**
* Distance between baseline and top of highest letter.
*
* @param fontSize the font size (in pt)
* @return the distance (in mm)
*/
double getAscender(int fontSize);
/**
* Distance between baseline and bottom of letter extending the farthest below the
* baseline.
*
* @param fontSize the font size (in pt)
* @return the distance (in mm)
*/
double getDescender(int fontSize);
/**
* Distance between the baselines of two consecutive text lines.
*
* @param fontSize the font size (in pt)
* @return the distance (in mm)
*/
double getLineHeight(int fontSize);
/**
* Returns the width of the specified text for the specified font size
*
* @param text text
* @param fontSize font size (in pt)
* @param isBold indicates if the text is in bold or regular weight
* @return width (in mm)
*/
double getTextWidth(CharSequence text, int fontSize, boolean isBold);
/**
* Splits the text into lines.
*
* If a line would exceed the specified maximum length, line breaks are
* inserted. Newlines are treated as fixed line breaks.
*
*
* @param text the text
* @param maxLength the maximum line length (in pt)
* @param fontSize the font size (in pt)
* @return an array of text lines
*/
String[] splitLines(String text, double maxLength, int fontSize);
}
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