GDI+

Rotation transform

• Demonstration (secured with demo version of Eziriz NET Reactor)
• Description:
  • Translation and rotation of an image
  • Use this sample picture - task06_Salvador_Dali_The_Temptation_of_St_Anthony.png (Salvador Dali's "The Temptation of St.Anthony")
• Functionality:
  • Image loaded form the program's resources
  • Image is always drawn in scale 100%, default location is (10,10)
  • Black dashed border is drawn around the image
  • Red circle (radius 5px) is drawn at each corner of the image
  • Green circle (radius 5px), a rotation center point, is drawn at image's center by default
  • Rotation center point, a green one, can be moved by mouse dragging
  • Image can be rotated around the green point by dragging one of the red points
    • Rotation angle determining
      
  • Whole image, including green point, can be moved by mouse dragging
  • Dragging outside the window should be possible
  • In window's caption cursor position in image space is presented
    • Image space has (0,0) in left upper corner of the image always
    • To transform point from client rectangle space into space of an image drawn using transformation matrix M, multiple point by inverted matrix M
  • AntiAlias has to be used, all the drawing should be flicker-free
• Hints:
  • Matrix class, Graphics class, Graphics.Transform.Transform property
  • Matrix.Clone(), Matrix.Invert(), Matrix.Translate(), Matrix.RotateAt(), Matrix.TransformPoints()
  • Math.Atan2(), Math.Sqrt()
  • DashStyle enumerator, SmoothingMode enumerator
  • Control.Invalidate(), Control.Capture property
• Approximate points:
  • image drawning (from resources) with border and points [2.0]
  • image translation [1.0]
  • independent green point translation [1.5]
  • dragging outside the window [0.5]
  • image rotation [4.0]
  • coordinates in window's caption [1.0]

• Links for uploading:
  • Solutions
  • Corrections