unipdf/creator/line.go

/*
 * This file is subject to the terms and conditions defined in
 * file 'LICENSE.md', which is part of this source code package.
 */

package creator

import (
	"math"

	"github.com/unidoc/unipdf/v3/contentstream/draw"
	"github.com/unidoc/unipdf/v3/model"
)

// Line defines a line between point 1 (X1,Y1) and point 2 (X2,Y2).  The line ending styles can be none (regular line),
// or arrows at either end.  The line also has a specified width, color and opacity.
// Implements the Drawable interface and can be drawn on PDF using the Creator.
type Line struct {
	x1        float64
	y1        float64
	x2        float64
	y2        float64
	lineColor *model.PdfColorDeviceRGB
	lineWidth float64
}

// newLine creates a new Line with default parameters between (x1,y1) to (x2,y2).
func newLine(x1, y1, x2, y2 float64) *Line {
	l := &Line{}

	l.x1 = x1
	l.y1 = y1
	l.x2 = x2
	l.y2 = y2

	l.lineColor = model.NewPdfColorDeviceRGB(0, 0, 0)
	l.lineWidth = 1.0

	return l
}

// GetCoords returns the (x1, y1), (x2, y2) points defining the Line.
func (l *Line) GetCoords() (float64, float64, float64, float64) {
	return l.x1, l.y1, l.x2, l.y2
}

// SetLineWidth sets the line width.
func (l *Line) SetLineWidth(lw float64) {
	l.lineWidth = lw
}

// SetColor sets the line color.
// Use ColorRGBFromHex, ColorRGBFrom8bit or ColorRGBFromArithmetic to make the color object.
func (l *Line) SetColor(col Color) {
	l.lineColor = model.NewPdfColorDeviceRGB(col.ToRGB())
}

// Length calculates and returns the line length.
func (l *Line) Length() float64 {
	return math.Sqrt(math.Pow(l.x2-l.x1, 2.0) + math.Pow(l.y2-l.y1, 2.0))
}

// GeneratePageBlocks draws the line on a new block representing the page. Implements the Drawable interface.
func (l *Line) GeneratePageBlocks(ctx DrawContext) ([]*Block, DrawContext, error) {
	block := NewBlock(ctx.PageWidth, ctx.PageHeight)

	drawline := draw.Line{
		LineWidth:        l.lineWidth,
		Opacity:          1.0,
		LineColor:        l.lineColor,
		LineEndingStyle1: draw.LineEndingStyleNone,
		LineEndingStyle2: draw.LineEndingStyleNone,
		X1:               l.x1,
		Y1:               ctx.PageHeight - l.y1,
		X2:               l.x2,
		Y2:               ctx.PageHeight - l.y2,
	}

	contents, _, err := drawline.Draw("")
	if err != nil {
		return nil, ctx, err
	}

	err = block.addContentsByString(string(contents))
	if err != nil {
		return nil, ctx, err
	}

	return []*Block{block}, ctx, nil
}