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I use the function below to draw a string on an image. It words great for the most part when I draw a string using one color.
However I want to have a word be in a different color. For example I want to draw "This is a TEST", I want TEST to be red.
What accomplish this using this method?
System.Drawing.Image newImg = new System.Drawing.Bitmap(500, 500);
pictureBox1.Image = TextOverlay(newImg, "This is a TEST", this.Font, Color.Black, ContentAlignment.MiddleCenter, 0.6F);
I'm referring to this line of code and not the OverlayColor parameter:
g.DrawString(OverlayText, f, b, rect, strFormat);
Here is the complete function:
public static Bitmap TextOverlay(Image img, string OverlayText, Font OverlayFont, Color OverlayColor, System.Drawing.ContentAlignment Position, float PercentFill)
{
// create bitmap and graphics used for drawing
// "clone" image but use 24RGB format
Bitmap bmp = new Bitmap(img.Width, img.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
Graphics g = Graphics.FromImage(bmp);
g.DrawImage(img, 0, 0);
int alpha = 255;
// Create the brush based on the color and alpha
SolidBrush b = new SolidBrush(Color.FromArgb(alpha, OverlayColor));
// Measure the text to render (unscaled, unwrapped)
StringFormat strFormat = StringFormat.GenericTypographic;
SizeF s = g.MeasureString(OverlayText, OverlayFont, 100000, strFormat);
// Enlarge font to specified fill (estimated by AREA)
float zoom = (float)(Math.Sqrt(((double)(img.Width * img.Height) * PercentFill) / (double)(s.Width * s.Height)));
FontStyle sty = OverlayFont.Style;
Font f = new Font(OverlayFont.FontFamily, ((float)OverlayFont.Size) * zoom, sty);
int charFit;
int linesFit;
float SQRTFill = (float)(Math.Sqrt(PercentFill));
strFormat.FormatFlags = StringFormatFlags.NoClip; //|| StringFormatFlags.LineLimit || StringFormatFlags.MeasureTrailingSpaces;
strFormat.Trimming = StringTrimming.Word;
SizeF layout = new SizeF(((float)img.Width) * SQRTFill, ((float)img.Height) * 1.5F); // fit to width, allow height to go over
s = g.MeasureString(OverlayText, f, layout, strFormat, out charFit, out linesFit);
// Determine draw area based on placement
RectangleF rect = new RectangleF((bmp.Width - s.Width) / 2F,
(bmp.Height - s.Height) / 2F,
layout.Width,
((float)img.Height) * SQRTFill);
// Add rendering hint (thx to Thomas)
g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
// finally, draw centered text!
g.DrawString(OverlayText, f, b, rect, strFormat);
// clean-up
g.Dispose();
b.Dispose();
f.Dispose();
return bmp;
}
I have this constructor that takes in an input of an array of Color objects and some misc strings (like file location and size of list), and stores this heatmap into a bitmap instance called _image_. Everything works out fine, but my main issue is I have no way to render text onto this heatmap. I would like to overlay title text and x and y-axis labels onto this bitmap.
public HeatMap(IEnumerable<Color> colors, int width, int height, string file, int U, int V) {
if (colors == null)
throw new ArgumentNullException("colors");
if (width <= 0)
throw new ArgumentException("width must be at least 1");
if (height <= 0)
throw new ArgumentException("height must be at least 1");
_width = width;
_height = height;
_file = file;
_image = new Bitmap(U, V, PixelFormat.Format32bppArgb);
Graphics graphics = Graphics.FromImage(_image);
graphics.Clear(Color.White);
graphics.Dispose();
int x = 0;
int y = 0;
foreach (Color color in colors) {
_image.SetPixel(x, y, color); // This can be speeded up by using GH_MemoryBitmap if you want.
y++;
if (y >= V) {
y = 0;
x++;
}
if (x >= U)
break;
}
}
Below, I also have a method that resizes the image (without too much distortion), and I figured I might as well make use of this since I have a graphics object I can use, like so:
private Bitmap ResizeBitmap(Bitmap sourceBMP, int width, int height) {
Bitmap result = new Bitmap(width, height);
using (Graphics g = Graphics.FromImage(result)) {
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
g.DrawImage(sourceBMP, 0, 0, width, height);
g.DrawString("A heatmap.", SystemFonts.DefaultFont, Brushes.Black, 10, 10);
}
return result;
}
Using the above, I was able to overlay text over it, as a starting point. My question is, how do I add a white boarder over the above image (so my text doesn't overlap my graph), and then overlay x and y-axis text onto it?
I guess my specific question really is - how do I render text onto, say, every four columns of my heatmap? In most instances, there are 100 x-axis objects, and like 24 y-axis objects. The y-axis would have the time of the day, while the x-axis has the day of the year. My familiarity with using graphics in C# is very low, so any pointers is very appreciated.
You've to use the DrawString before the graphics.Dispose() and after the Clear().
Graphics graphics = Graphics.FromImage(_image);
graphics.Clear(Color.WhiteSmoke);
graphics.DrawString("your text", SystemFonts.DefaultFont, Brushes.Black, new PointF(0, 0));
graphics.Dispose();
Where the PointF(0, 0) represents the up-left corner of your text placeholder, you've to calculate the text position based on the positions of your heatmap.
UPDATE (alignment)
You can align your text in relation with a virtual rectangle, doing something like:
Graphics graphics = Graphics.FromImage(_image);
graphics.Clear(Color.WhiteSmoke);
StringFormat stringFormat = new StringFormat() { Alignment = StringAlignment.Center, LineAlignment = StringAlignment.Center };
graphics.DrawString("your text", SystemFonts.DefaultFont, Brushes.Black, new RectangleF(0, 0, 100, 100), stringFormat);
graphics.Dispose();
In this case I've created a virtual box of 100x100 positioned on the top-left corner, and the text is h/v centered relatively to this box.
Building a little paint program and am trying to incorporate the concept of layers.
I'm using a PictureBox control to display the image, and getting the Graphics object from the image being displayed by the PictureBox and drawing to that.
My problem is I'm trying to figure out how to draw to a new Graphics object that is overlayed on top of the picture box, and be able to get the newly drawn image without the original image absorbed into the graphic.
If I do something like:
Graphics gr = Graphics.FromImage(myPictureBox.image);
gr.DrawRectangle(blah blah)
...I am editing the original image in the picture box. I want a way to only capture the new stuff being drawn as a separate image, but still have it displayed as an overlay over top of what was already there.
Anyone able to point me in the right direction? Thanks!
I would reckon to use the transparent control and do some modification so it can be used as image layers:
http://www.codeproject.com/Articles/26878/Making-Transparent-Controls-No-Flickering
Probably something like this (make any modification as necessary).
class LayerControl : UserControl
{
private Image image;
private Graphics graphics;
public LayerControl(int width, int height)
{
this.Width = width;
this.Height = height;
image = new Bitmap(width, height);
graphics = Graphics.FromImage(image);
// Set style for control
SetStyle(ControlStyles.OptimizedDoubleBuffer |
ControlStyles.AllPaintingInWmPaint |
ControlStyles.UserPaint, true);
}
// this function will draw your image
protected override void OnPaint(PaintEventArgs e)
{
var bitMap = new Bitmap(image);
// by default the background color for bitmap is white
// you can modify this to follow your image background
// or create a new Property so it can dynamically assigned
bitMap.MakeTransparent(Color.White);
image = bitMap;
Graphics g = e.Graphics;
g.SmoothingMode = SmoothingMode.AntiAlias;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.CompositingQuality = CompositingQuality.GammaCorrected;
float[][] mtxItens = {
new float[] {1,0,0,0,0},
new float[] {0,1,0,0,0},
new float[] {0,0,1,0,0},
new float[] {0,0,0,1,0},
new float[] {0,0,0,0,1}};
ColorMatrix colorMatrix = new ColorMatrix(mtxItens);
ImageAttributes imgAtb = new ImageAttributes();
imgAtb.SetColorMatrix(
colorMatrix,
ColorMatrixFlag.Default,
ColorAdjustType.Bitmap);
g.DrawImage(image,
ClientRectangle,
0.0f,
0.0f,
image.Width,
image.Height,
GraphicsUnit.Pixel,
imgAtb);
}
// this function will grab the background image to the control it self
protected override void OnPaintBackground(PaintEventArgs e)
{
base.OnPaintBackground(e);
Graphics g = e.Graphics;
if (Parent != null)
{
BackColor = Color.Transparent;
int index = Parent.Controls.GetChildIndex(this);
for (int i = Parent.Controls.Count - 1; i > index; i--)
{
Control c = Parent.Controls[i];
if (c.Bounds.IntersectsWith(Bounds) && c.Visible)
{
Bitmap bmp = new Bitmap(c.Width, c.Height, g);
c.DrawToBitmap(bmp, c.ClientRectangle);
g.TranslateTransform(c.Left - Left, c.Top - Top);
g.DrawImageUnscaled(bmp, Point.Empty);
g.TranslateTransform(Left - c.Left, Top - c.Top);
bmp.Dispose();
}
}
}
else
{
g.Clear(Parent.BackColor);
g.FillRectangle(new SolidBrush(Color.FromArgb(255, Color.Transparent)), this.ClientRectangle);
}
}
// simple drawing circle function
public void DrawCircles()
{
using (Brush b = new SolidBrush(Color.Red))
{
using (Pen p = new Pen(Color.Green, 3))
{
this.graphics.DrawEllipse(p, 25, 25, 20, 20);
}
}
}
// simple drawing rectable function
public void DrawRectangle()
{
using (Brush b = new SolidBrush(Color.Red))
{
using (Pen p = new Pen(Color.Red, 3))
{
this.graphics.DrawRectangle(p, 50, 50, 40, 40);
}
}
}
// Layer control image property
public Image Image
{
get
{
return image;
}
set
{
image = value;
// this will make the control to be redrawn
this.Invalidate();
}
}
}
Example how to use it:
LayerControl lc = new LayerControl(100, 100);
lc.Location = new Point(0, 0);
lc.DrawRectangle();
LayerControl lc2 = new LayerControl(100, 100);
lc2.Location = new Point(0, 0);
lc2.DrawCircles();
LayerControl lc3 = new LayerControl(100, 100);
lc3.Location = new Point(0, 0);
lc3.Image = new Bitmap(#"<Image Path>");
// adding control
this.Controls.Add(dc);
this.Controls.Add(dc2);
this.Controls.Add(dc3);
With this method you can have multiple layers that can put overlapping each other (due to the transparency feature it has).
If you want to add it in top of your PictureBox make sure to re-order the control. The Layer Control should be added before your PictureBox control.
// adding control
this.Controls.Clear();
this.Controls.Add(dc);
this.Controls.Add(dc2);
this.Controls.Add(dc3);
this.Controls.Add(PictureBox1);
Hopefully it help.
example code which working fine - take dummy image and layered the original image with custom text
public void LayerImage(System.Drawing.Image Current, int LayerOpacity)
{
Bitmap bitmap = new Bitmap(Current);
int h = bitmap.Height;
int w = bitmap.Width;
Bitmap backg = new Bitmap(w, h + 20);
Graphics g = null;
try
{
g = Graphics.FromImage(backg);
g.Clear(Color.White);
Font font = new Font("Arial", 12, FontStyle.Bold, GraphicsUnit.Pixel);
RectangleF rectf = new RectangleF(70, 90, 90, 50);
Color color = Color.FromArgb(255, 128, 128, 128);
Point atpoint = new Point(backg.Width / 2, backg.Height - 10);
SolidBrush brush = new SolidBrush(color);
StringFormat sf = new StringFormat();
sf.Alignment = StringAlignment.Center;
sf.LineAlignment = StringAlignment.Center;
g.DrawString("BRAND AMBASSADOR", font, brush, atpoint, sf);
g.Dispose();
MemoryStream m = new MemoryStream();
backg.Save(m, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch { }
Color pixel = new Color();
for (int x = 0; x < bitmap.Width; x++)
{
for (int y = 0; y < bitmap.Height; y++)
{
pixel = bitmap.GetPixel(x, y);
backg.SetPixel(x, y, Color.FromArgb(LayerOpacity, pixel));
}
}
MemoryStream m1 = new MemoryStream();
backg.Save(m1, System.Drawing.Imaging.ImageFormat.Jpeg);
m1.WriteTo(Response.OutputStream);
m1.Dispose();
base.Dispose();
}
Got it working, perhaps I wasn't clear enough in my original question.
Essentially what I ended up doing was storing each layer as a separate Image object, then just hooking into the OnPaint method of my control and manually drawing the graphics in order, instead of just drawing to PictureBox.Image. Works like a charm!
The graphics capabilities of .NET drawing libraries are simple. Their main purpose is direct drawing of GUI. If you want to have layering, alpha transparency or advanced filters, then you should either use 3rd party library or roll your own drawing code.
I want to add 2 string to an image as follows:
This is Text
------------
------------
------------
--Other-----
How do I use the largest font size possible without have the String go off the side of the image?
example: if text is too big then it goes off the image::
This is Text That is too big
------------
------------
------------
--Other-----
I wrote this script on my previous projects to fit some text into the image by calculating its dimensions for each font-size. when the font size is bigger than the image's width, it lowers the font size by 0.1em and tries again until the text fits in the image. Here's the code :
public static string drawTextOnMarker(string markerfile, string text, string newfilename,Color textColor)
{
//Uri uri = new Uri(markerfile, UriKind.Relative);
//markerfile = uri.AbsolutePath;
//uri = new Uri(newfilename, UriKind.Relative);
//newfilename = uri.AbsolutePath;
if (!System.IO.File.Exists(System.Web.HttpContext.Current.Server.MapPath(newfilename)))
{
try
{
Bitmap bmp = new Bitmap(System.Web.HttpContext.Current.Server.MapPath(markerfile));
Graphics g = Graphics.FromImage(bmp);
g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAliasGridFit;
StringFormat strFormat = new StringFormat();
strFormat.Alignment = StringAlignment.Center;
SolidBrush myBrush = new SolidBrush(textColor);
float fontsize = 10;
bool sizeSetupCompleted = false;
while (!sizeSetupCompleted)
{
SizeF mySize = g.MeasureString(text, new Font("Verdana", fontsize, FontStyle.Bold));
if (mySize.Width > 24 || mySize.Height > 13)
{
fontsize-= float.Parse("0.1");
}
else
{
sizeSetupCompleted = true;
}
}
g.DrawString(text, new Font("Verdana", fontsize, FontStyle.Bold), myBrush, new RectangleF(4, 3, 24, 8), strFormat);
bmp.Save(System.Web.HttpContext.Current.Server.MapPath(newfilename));
return newfilename.Substring(2);
}
catch (Exception)
{
return markerfile.Substring(2);
}
}
return newfilename.Substring(2);
}
Here is a quick solution:
using (Graphics g = Graphics.FromImage(bmp))
{
float width = g.MeasureString(text, font).Width;
float scale = bmp.Width / width;
g.ScaleTransform(scale, scale); //Simple trick not to use other Font instance
g.DrawString(text, font, Brushes.Black, PointF.Empty);
g.ResetTransform();
...
}
Your text won't be always 100% width if you use TextRenderingHint.AntiAliasGridFit or similar, but I think that's not a problem as you just want to make sure the text alawys fits in the image.
I'm trying to draw a series of connected segments, but the curved segments seem to produce an artifact, whereby the outer side of the curve is not smooth at all, but very jagged. This is part of a GIS program I am making.
For these lines, the line itself needs to be quite wide, as this represents the range of data that can be collected on this line for the GIS data. There also has to be an area directly under the line where no data is collected. This also can be wide, but not as wide as the main line.
I have done this using a graphics path, which I then widen and use as a clipping region to block the area directly under the line. I then draw the actual line. The sample code below does this, with made up values for ease of regenerating.
This works fine with straight lines, but with curved lines there are very irregular shapes on the outside of the curves. I have no idea why this happens.
Any ideas would be much appreciated, cheers,
Greg
I made this sample code using a basic form with a picturebox and a button on it, whereby when I clicked the button it would execute this method:
private void drawCurvedLine()
{
//initialise the plot area:
Bitmap image = new Bitmap(pictureBox1.Width, pictureBox1.Height);
pictureBox1.BackgroundImage = image;
Graphics g = Graphics.FromImage(image);
//the width of the pen represents the width of a sonar swathe:
Pen widePen = new Pen(new SolidBrush(Color.FromArgb(80, Color.Blue)), 50);
PointF[] points = new PointF[4];
//first straight:
points[0] = new PointF(287.284149F,21.236269F);
points[1] = new PointF(183.638443F,406.936249F);
//second straight:
points[2] = new PointF(130.842773F, 515.574036F);
points[3] = new PointF(-1950.91321F, 3491.868F);
//graphics path for the line:
GraphicsPath gPath = new GraphicsPath();
gPath.AddLine(points[0], points[1]);
gPath.AddArc(new RectangleF(-445.464447F,3.84924316F,640.067444F,640.067444F), -(90 - 105.0412369999982F), 10.8775282F);
gPath.AddArc(new RectangleF(-445.464417F, 3.84915161F, 640.067444F, 640.067444F), -(90 - 115.91811484539707F), 10.8775091F);
gPath.AddLine(points[2], points[3]);
//widen the line to the width equal to what the fish will not be able to see:
gPath.Widen(new Pen(Color.White, 10));
//now exclude that widened line from the main graphics:
g.ExcludeClip(new Region(gPath));
//draw the swathe line:
g.DrawPath(widePen, gPath);
//reset the clipping for the next line:
g.ResetClip();
}
Try to use a separate GraphicsPath for excluded region:
private void drawCurvedLine()
{
//initialise the plot area:
Bitmap image = new Bitmap(pictureBox1.Width, pictureBox1.Height);
pictureBox1.BackgroundImage = image;
using(Graphics g = Graphics.FromImage(image))
{
PointF[] points = new PointF[4];
//first straight:
points[0] = new PointF(287.284149F, 21.236269F);
points[1] = new PointF(183.638443F, 406.936249F);
//second straight:
points[2] = new PointF(130.842773F, 515.574036F);
points[3] = new PointF(-1950.91321F, 3491.868F);
//graphics path for the line:
using(GraphicsPath gPath = new GraphicsPath())
{
gPath.AddLine(points[0], points[1]);
gPath.AddArc(new RectangleF(-445.464447F, 3.84924316F, 640.067444F, 640.067444F), -(90 - 105.0412369999982F), 10.8775282F);
gPath.AddArc(new RectangleF(-445.464417F, 3.84915161F, 640.067444F, 640.067444F), -(90 - 115.91811484539707F), 10.8775091F);
gPath.AddLine(points[2], points[3]);
//widen the line to the width equal to what the fish will not be able to see:
using(GraphicsPath innerPath = (GraphicsPath)gPath.Clone())
{
using(Pen pen = new Pen(Color.White, 10))
{
innerPath.Widen(pen);
}
//now exclude that widened line from the main graphics:
using(Region reg = new Region(innerPath))
{
g.ExcludeClip(reg);
//draw the swathe line:
//the width of the pen represents the width of a sonar swathe:
using(Pen widePen = new Pen(new SolidBrush(Color.FromArgb(80, Color.Blue)), 50))
{
g.DrawPath(widePen, gPath);
}
//reset the clipping for the next line:
g.ResetClip();
}
}
}
}
}
Set the smoothing mode properly on your Graphics instance. Take a look here.
Try setting the CompositingQuality, the InterpolationMode and the SmoothingMode properties to increase the quality of your Graphics object:
using(Graphics g = Graphics.FromImage(image))
{
g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
g.SmoothingMode = SmoothingMode.AntiAlias;
//...
}