C # drawing PDF Graphics-Basic graphics, custom graphics, color transparency

Introduction

In the PDF we can add very rich elements to the content we want to express through C # program code, such as drawing tables, text, adding graphics, images, and so on. In this article, I'll show you how to draw a graphic in a PDF and set the operation of a graphic property.

The article will be described in the following points:

1. Draw Basic shapes (lines, ellipses, circles, rectangles, triangles)
2. Drawing a custom graphic
3. Draw graphics and set graphic transparency
   Tools Required : Spire.pdf for. NET 4.0

tip : After installation, directly refer to the DLL file in the Bin folder under the installation path to the project program.

"Example 1" draws a basic graphic

Step 1: create a new PDF document, add a page, add a brush, paint a brush

           //新建一个PDF文档，添加页            PdfDocument doc = new PdfDocument();            PdfPageBase page = doc.Pages.Add();            //设置画笔和画刷            PdfPen pen = new PdfPen(PdfBrushes.Black, 1f);            PdfBrush brush1 = PdfBrushes.RosyBrown;            PdfBrush brush2 = PdfBrushes.Goldenrod;

Step 2: draw a circle, rectangle, line segment, triangle

            //绘入矩形（此处通过设置值来绘制成正方形）            page.Canvas.DrawRectangle(pen, brush1, new Rectangle(new Point(50, 50), new Size(60, 60)));            //绘入椭圆（此处通过设置值来绘制成圆形）            page.Canvas.DrawEllipse(pen, brush2, 210, 50, 60, 60);            //绘入线段            page.Canvas.DrawLine(pen, new PointF(50, 115), new PointF(270, 115));            //绘入多边形（此处绘制成三角形）            PointF p1 = new PointF(130, 172);            PointF p2 = new PointF(160, 120);            PointF p3 = new PointF(190, 172);            PointF[] points = new PointF[] { p1, p2, p3 };            page.Canvas.DrawPolygon(pen, points);

Step 3: Save the document

            //保存并打开文档            doc.SaveToFile("基本图形.pdf");            System.Diagnostics.Process.Start("基本图形.pdf");

Graphics Add Effect:

"Example 2" drawing a custom graphic

Step 1: Create a PDF document, call Method Drawstar () to draw a custom graphic, and save

            //新建一个PDF文档，添加页            PdfDocument doc = new PdfDocument();            PdfPageBase page = doc.Pages.Add();            //调用DrawStar()方法绘入五角星图形            DrawStar(page);            //保存并打开文档            doc.SaveToFile("自定义图形.pdf");            System.Diagnostics.Process.Start("自定义图形.pdf");

Step 2: Customize the Drawstar () method to draw several different styles of pentagram

private static void Drawstar (Pdfpagebase page) {//Set 5 vertex coordinates of a pentagram pointf[] points = new pointf[            5]; for (int i = 0; i < points. Length;                i++) {float x = (float) math.cos (i * 2 * MATH.PI/5);                Float y = (float) Math.sin (i * 2 * MATH.PI/5);            Points[i] = new PointF (x, y);            }//Create the Pdfpath class to add segments between vertices to form the pentagram pdfpath path = new Pdfpath (); Path.            AddLine (Points[2], points[0]); Path.            AddLine (Points[0], points[3]); Path.            AddLine (Points[3], points[1]); Path.            AddLine (Points[1], points[4]); Path.            AddLine (Points[4], points[2]); Save Canvas status Pdfgraphicsstate state = page.            Canvas.save ();            Instantiate brushes and brushes 1, brush 2 pdfpen pen = new PDFpen (Color.deepskyblue, 0.02f);            Pdfbrush brush1 = new Pdfsolidbrush (color.palegreen);            Pdfbrush brush2 = new Pdfsolidbrush (color.bisque); The coordinatesZoom in 40 times times page.            Canvas.scaletransform (40f, 40f); The translation coordinates page.            Canvas.translatetransform (1f, 1.5f); Draw in the first Pentagram page.            Canvas.drawpath (pen, path); Translates the coordinates and draws the second Pentagram page at the new location.            Canvas.translatetransform (2f, 0f); Path.            Fillmode = pdffillmode.alternate; Page.            Canvas.drawpath (pen, brush1, PATH); Translates the coordinates and draws a third pentagram page in the new location.            Canvas.translatetransform (2f, 0f); Path.            Fillmode = pdffillmode.winding; Page.            Canvas.drawpath (pen, BRUSH2, PATH); Instantiate a brush 3, translate the coordinates and draw the fourth pentagram in the new position pdflineargradientbrush BRUSH3 = new Pdflineargradientbrush (new point            F ( -2, 0), New PointF (2, 0), color.orangered, Color.yellow); Page.            Canvas.translatetransform ( -4f, 2f); Path.            Fillmode = pdffillmode.alternate; Page.            Canvas.drawpath (pen, BRUSH3, PATH);              Instantiate a brush 4, translate the coordinates and draw the fifth pentagram in the new position Pdfradialgradientbrush BRUSH4  = new Pdfradialgradientbrush (new PointF (0f, 0f), 0f, New PointF (0f, 0f), 1f, Color.orchid, Color.lightblue); Page.            Canvas.translatetransform (2f, 0f); Path.            Fillmode = pdffillmode.winding; Page.            Canvas.drawpath (pen, brush4, PATH);            Instantiate the brush 5, translate the coordinates and draw in the new position the sixth pentagram Pdftilingbrush Brush5 = new Pdftilingbrush (new RectangleF (0, 0, 4f, 4f)); Brush5.            Graphics.drawrectangle (BRUSH3, 0, 0, 4f, 4f); Page.            Canvas.translatetransform (2f, 0f); Path.            Fillmode = pdffillmode.winding; Page.            Canvas.drawpath (pen, brush5, PATH); Save the Canvas state page again.        Canvas.restore (state); }

Custom Graphics Add Effects:

"Example 3" Set color transparency

Step 1: Create a new PDF document, add a page

            PdfDocument doc = new PdfDocument();            PdfPageBase page = doc.Pages.Add();

Step 2: Initialize an Pdfseparationcolorspace object to create the base color and set the base color transparency to 1

             PdfSeparationColorSpace cs1 = new PdfSeparationColorSpace("MySpotColor", Color.DarkGreen);            PdfSeparationColorSpace cs2 = new PdfSeparationColorSpace("MySpotColor", Color.Yellow);            PdfSeparationColorSpace cs3 = new PdfSeparationColorSpace("MySpotColor", Color.DeepPink);            PdfSeparationColor color1 = new PdfSeparationColor(cs1, 1f);            PdfSeparationColor color2 = new PdfSeparationColor(cs2, 1f);            PdfSeparationColor color3 = new PdfSeparationColor(cs3, 1f);

Step 3: Create a brush based on color

            PdfSolidBrush brush1 = new PdfSolidBrush(color1);            PdfSolidBrush brush2 = new PdfSolidBrush(color2);            PdfSolidBrush brush3 = new PdfSolidBrush(color3);

Step 4: Draw in graphics and text, apply color transparency to graphics

            Draws graphics and text and coloring page.            Canvas.drawpie (BRUSH1, 10, 30, 60, 60, 360, 360); Page.            Canvas.drawpie (BRUSH2, 10, 120, 60, 60, 360, 360); Page.            Canvas.drawpie (BRUSH3, 10, 210, 60, 60, 360, 360); Page.            Canvas.drawstring ("Transparency =1.0", New Pdftruetypefont ("Arial Unicode MS", 10f), true), Brush1, New PointF (16, 100));            Set the basic color transparency to 0.5 and draw the picture and text Color1 = new Pdfseparationcolor (CS1, 0.5f);            BRUSH1 = new Pdfsolidbrush (color1); Page.            Canvas.drawpie (BRUSH1, 80, 30, 60, 60, 360, 360);            Color2 = new Pdfseparationcolor (CS2, 0.5f);            BRUSH2 = new Pdfsolidbrush (COLOR2); Page.            Canvas.drawpie (BRUSH2, 80, 120, 60, 60, 360, 360);            Color3 = new Pdfseparationcolor (CS3, 0.5f);            BRUSH3 = new Pdfsolidbrush (COLOR3); Page.            Canvas.drawpie (BRUSH3, 80, 210, 60, 60, 360, 360); Page. Canvas.drawstring ("Transparency =0.5", New Pdftruetypefont ("Arial Unicode MS", 10f), True), Brush1, New PointF (86, 100));            Set the basic color transparency to 0.25 and draw the picture and text Color1 = new Pdfseparationcolor (CS1, 0.25f);            BRUSH1 = new Pdfsolidbrush (color1); Page.            Canvas.drawpie (BRUSH1, 150, 30, 60, 60, 360, 360);            Color2 = new Pdfseparationcolor (CS2, 0.25f);            BRUSH2 = new Pdfsolidbrush (COLOR2); Page.            Canvas.drawpie (BRUSH2, 150, 120, 60, 60, 360, 360);            Color3 = new Pdfseparationcolor (CS3, 0.25f);            BRUSH3 = new Pdfsolidbrush (COLOR3); Page.            Canvas.drawpie (BRUSH3, 150, 210, 60, 60, 360, 360); Page. Canvas.drawstring ("Transparency =0.25", new Pdftruetypefont (New Font ("Arial Unicode MS", 10f), true), Brush1, New PointF (156, 100)) ;

Step 5: Save the document

            doc.SaveToFile("设置透明度.pdf");            System.Diagnostics.Process.Start("设置透明度.pdf");

Color transparency achieves the effect:

The above is about C # to draw the entire content of PDF graphics, if you want to reprint, please specify the source!
(End of this article)

C # drawing PDF Graphics-Basic graphics, custom graphics, color transparency