Saving higher resolution charts without messing up the appearance

Question

you\'ll all have to excuse my ignorance as I have only recently started working with C#. I just have a question about the windows chart control, as I\'m encountering a rathe

Answer 1

Create/Duplicate a hidden (Visible = false) chart object on the form. You can even set its Top and Left properties to be off of the form. Set this control to a very high Width and Height (i.e., 2100 x 1500)... Populate and format it to your specifications. Be sure to increase the font sizes, etc. Then call SaveImage() or DrawToBitmap() from the hidden chart...

When you save this file, it will essentially be high enough resolution for most word processing, desktop pubs, printing, etc. For example, 2100 x 1500 @ 300 dpi = 7" x 5" for printing...

In your application, you can also scale it down or print it: scaling down "adds" resolution, so the image becomes sharper. Scaling up makes an image blurry or fuzzy.

I have had to rely on this technique, as it is the most consistent way to get high-res charts from the .Net chart control for printing or saving... It is a classic cheat, but it works :)

For example:

private void cmdHidden_Click(object sender, EventArgs e) {
    System.Windows.Forms.DataVisualization.Charting.Title chtTitle =
        new System.Windows.Forms.DataVisualization.Charting.Title();
    System.Drawing.Font chtFont = new System.Drawing.Font("Arial", 42);
    string[] seriesArray = { "A", "B", "C" };
    int[] pointsArray = { 1, 7, 4 };

    chart1.Visible = false;
    chart1.Width = 2100;
    chart1.Height = 1500;
    chart1.Palette = System.Windows.Forms.DataVisualization.Charting.ChartColorPalette.Bright;

    chtTitle.Font = chtFont;
    chtTitle.Text = "Demographics Comparison";
    chart1.Titles.Add(chtTitle);

    chart1.Series.Clear();

    // populate chart    
    for (int i = 0; i < seriesArray.Length; i++) {
        Series series = chart1.Series.Add(seriesArray[i]);
        series.Label = seriesArray[i].ToString();
        series.Font = new System.Drawing.Font("Arial", 24);
        series.ShadowOffset = 5;
        series.Points.Add(pointsArray[i]);
    }

    // save from the chart object itself
    chart1.SaveImage(@"C:\Temp\HiddenChart.png", ChartImageFormat.Png);

    // save to a bitmap
    Bitmap bmp = new Bitmap(2100, 1500);
    chart1.DrawToBitmap(bmp, new Rectangle(0, 0, 2100, 1500));
    bmp.Save(@"C:\Temp\HiddenChart2.png");
}

Answer 2

Try setting chart2.RenderTransform = new ScaleTransform(10,10) and save it. This should also make your lines bigger.

Answer 3

Here's a class I made to make a larger graph, save it, then restore the graph. Works well for my my purposes.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using OfficeOpenXml.Drawing;
using OfficeOpenXml.Drawing.Chart;
using System.Drawing.Imaging;
using System.Windows.Forms.DataVisualization.Charting;
using System.Windows.Forms;

namespace Simple_Grapher
{
    class saveQualityChartImage
    {
        Chart theChart;
        System.Drawing.Font oldFont1 = new System.Drawing.Font("Trebuchet MS", 35F, System.Drawing.FontStyle.Bold);
        System.Drawing.Font oldFont2 = new System.Drawing.Font("Trebuchet MS", 15F, System.Drawing.FontStyle.Bold);
        System.Drawing.Font oldFont3 = new System.Drawing.Font("Trebuchet MS", 35F, System.Drawing.FontStyle.Bold);
        System.Drawing.Font oldLegendFont = new System.Drawing.Font("Trebuchet MS", 35F, System.Drawing.FontStyle.Bold);

        int oldLineWidth1;
        int oldLineWidth2;
        int oldLineWidth3;
        int oldLineWidth4;

        int oldWidth;
        int oldHeight;
        public saveQualityChartImage(Chart inputChart)
        {
            if (!(inputChart.Series.Count > 0))
            {
                return;
            }
            theChart = inputChart;
            if (inputChart.Titles.Count > 0)
            {
                oldFont1 = inputChart.Titles[0].Font;
            }
            oldFont2 = inputChart.ChartAreas[0].AxisX.LabelStyle.Font;
            oldFont3 = inputChart.ChartAreas[0].AxisX.TitleFont;
            if (theChart.Legends.Count > 0)
            {
                oldLegendFont = theChart.Legends["Legend"].Font;
            }
            oldLineWidth1 = theChart.ChartAreas[0].AxisX.LineWidth;
            oldLineWidth2 = theChart.ChartAreas[0].AxisX.MajorTickMark.LineWidth;
            oldLineWidth3 = theChart.Series[0].BorderWidth;
            oldLineWidth4 = theChart.ChartAreas[0].AxisY.MajorGrid.LineWidth;
            oldWidth = theChart.Width;
            oldHeight = theChart.Height;

            saveimage();
        }

        public void saveimage()
        {
            theChart.Visible = false;
            System.Drawing.Font chtFont = new System.Drawing.Font("Trebuchet MS", 35F, System.Drawing.FontStyle.Bold);
            System.Drawing.Font smallFont = new System.Drawing.Font("Trebuchet MS", 15F, System.Drawing.FontStyle.Bold);
            if (theChart.Titles.Count > 0)
            {
                theChart.Titles[0].Font = chtFont;
            }

            theChart.ChartAreas[0].AxisX.TitleFont = chtFont;
            theChart.ChartAreas[0].AxisX.LineWidth = 3;
            theChart.ChartAreas[0].AxisX.MajorGrid.LineWidth = 3;
            theChart.ChartAreas[0].AxisX.LabelStyle.Font = smallFont;
            theChart.ChartAreas[0].AxisX.MajorTickMark.LineWidth = 3;

            theChart.ChartAreas[0].AxisY.TitleFont = chtFont;
            theChart.ChartAreas[0].AxisY.LineWidth = 3;
            theChart.ChartAreas[0].AxisY.MajorGrid.LineWidth = 3;
            theChart.ChartAreas[0].AxisY.LabelStyle.Font = smallFont;
            theChart.ChartAreas[0].AxisY.MajorTickMark.LineWidth = 3;
            if (theChart.Legends.Count > 0)
            {
                theChart.Legends["Legend"].Font = smallFont;
            }


            foreach (Series series in theChart.Series)
            {
                series.BorderWidth = 3;

            }

            theChart.Width = 1800;
            theChart.Height = 1200;

            SaveFileDialog save = new SaveFileDialog();
            save.DefaultExt = ".png";
            if (save.ShowDialog() == DialogResult.OK)
            {
                theChart.SaveImage(save.FileName, ChartImageFormat.Png);
            }
            resetOldValues();

        }

        private void resetOldValues()
        {
            if (theChart.Titles.Count > 0)
            {
                theChart.Titles[0].Font = oldFont1;
            }

            theChart.ChartAreas[0].AxisX.TitleFont = oldFont3;
            theChart.ChartAreas[0].AxisX.LineWidth = oldLineWidth1;
            theChart.ChartAreas[0].AxisX.MajorGrid.LineWidth = oldLineWidth4;
            theChart.ChartAreas[0].AxisX.LabelStyle.Font = oldFont2;
            theChart.ChartAreas[0].AxisX.MajorTickMark.LineWidth = oldLineWidth2;

            theChart.ChartAreas[0].AxisY.TitleFont = oldFont3;
            theChart.ChartAreas[0].AxisY.LineWidth = oldLineWidth1;
            theChart.ChartAreas[0].AxisY.MajorGrid.LineWidth = oldLineWidth4;
            theChart.ChartAreas[0].AxisY.LabelStyle.Font = oldFont2;
            theChart.ChartAreas[0].AxisY.MajorTickMark.LineWidth = oldLineWidth2;
            if (theChart.Legends.Count > 0)
            {
                theChart.Legends["Legend"].Font = oldLegendFont;
            }



            foreach (Series series in theChart.Series)
            {
                series.BorderWidth = oldLineWidth3;

            }

            theChart.Width = oldWidth;
            theChart.Height = oldHeight;
            theChart.Visible = true;   
        }  
    }
}