Category Archives: transformations

Map device coordinates to world coordinates in C#

Posted on January 17, 2018 by Rod Stephens

Sometimes it’s convenient to draw in one coordinate system (called world coordinates) and map those coordinates to the screen’s device coordinates. The example Map points between coordinate systems in C# shows how to do this in C#. For example, the … Continue reading →

Posted in drawing, graphics, transformations | Tagged C#, C# programming, coordinates, device coordinates, drawing, example, example program, graphics, transformations, Windows Forms programming, world coordinates | Leave a comment

Draw improved text on a curve in C#

Posted on August 23, 2017 by RodStephens

This example shows how to draw improved text along a curved path. The example Draw text on a curve in C# shows how to draw text along a curved path. Unfortunately the spacing between the letters is pretty mediocre in … Continue reading →

Posted in algorithms, drawings, fonts, graphics, transformations | Tagged algorithms, C#, C# programming, curves, draw improved text, draw text, draw text on a curve, drawing, example, example program, fonts, graphics, text, text on a curve, transformations, Windows Forms programming | Leave a comment

Rotate images that are scaled in C#

Posted on February 3, 2017 by RodStephens

The example Interactively rotate images in C# lets you click and drag to rotate images but it doesn’t always work well if the image you are rotating is too big to fit on the screen. The example Rotate images inside … Continue reading →

Posted in algorithms, graphics, image processing, transformations | Tagged algorithms, AutoSize, C#, C# programming, example, example program, graphics, image processing, Panel, rotate image, rotate scaled images, scaled images, scroll bars, transformations, Windows Forms programming | 14 Comments

Rotate images inside a scrolled panel in C#

Posted on February 2, 2017 by RodStephens

The example Interactively rotate images in C# lets you click and drag to rotate images. Unfortunately it doesn’t work well with images that are too big to fit on the screen. If an image is too big, the program lets … Continue reading →

Posted in algorithms, graphics, image processing, transformations | Tagged algorithms, C#, C# programming, example, example program, graphics, image processing, Panel, rotate image, scroll bars, scrolled panel, transformations, Windows Forms programming | Leave a comment

Interactively rotate images in C#

Posted on March 2, 2016 by Rod Stephens

The example Rotate images by an arbitrary angle in C# explains how you can rotate an image by a angle specified in a TextBox. This example lets you click and drag around the image’s center to specify the angle of … Continue reading →

Posted in algorithms, graphics, image processing, transformations | Tagged algorithmsrotate image, C#, C# programming, example, example program, graphics, image processing, transformations, Windows Forms programming | 8 Comments

Rotate images in C#

Posted on March 2, 2016 by Rod Stephens

This program uses the following RotateBitmap method to rotate an image. // Return a bitmap rotated around its center. private Bitmap RotateBitmap(Bitmap bm, float angle) { // Make a Matrix to represent rotation // by this angle. Matrix rotate_at_origin = … Continue reading →

Posted in algorithms, graphics, image processing, transformations | Tagged algorithms, C#, C# programming, example, example program, graphics, image processing, rotate image, transformations, Windows Forms programming | 6 Comments

Easily map drawing coordinates in C#

Posted on February 8, 2016 by RodStephens

The example Map points between coordinate systems in C# shows several ways you can map drawing coordinates to screen coordinates. They all work but these sorts of coordinate conversions are really common if you’re doing more advanced graphics so I … Continue reading →

Posted in drawing, graphics, transformations | Tagged C#, C# programming, device coordinates, drawing, drawing coordinates, example, example program, graphics, map coordinates, Matrix, rotate, rotation, scale, scaling, transform, transformations, translate, translation, Windows Forms programming, world coordinates | 1 Comment

Draw text on a line segment in C#

Posted on January 26, 2016 by Rod Stephens

This example shows how you can draw text on a line segment. The key is the DrawTextOnSegment method shown in the following code. This method can draw text on a line segment or below a line segment. // Draw some … Continue reading →

Posted in algorithms, drawing, fonts, graphics, transformations | Tagged algorithms, C#, C# programming, draw text, draw text on a line, draw text on a line segment, drawing, example, example program, fonts, graphics, line segment, text, text on a line segment, transformations, Windows Forms programming | Leave a comment

Make CAPTCHA images with overlapping characters in C#

Posted on January 28, 2015 by Rod Stephens

The following MakeCaptchaImage2 method creates a Bitmap containing a CAPTCHA image. private Random Rand = new Random(); // Draw the words with letters overlapping each other. private Bitmap MakeCaptchaImage2(string txt, int wid, int hgt, Font the_font, Brush the_brush) { Bitmap … Continue reading →

Posted in drawing, graphics, image processing, internet, transformations, web | Tagged C#, C# programming, CAPTCHA, CAPTCHA images, drawing, example, example program, graphics, image processing, internet, transformations, web, Windows Forms programming | Leave a comment

Make CAPTCHA images in C#

Posted on January 28, 2015 by Rod Stephens

CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) images are those distorted pictures of words that some Web sites make you enter to prove you are a human and not an automated process. The idea is … Continue reading →