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Painting a projectile's curve GDI
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David_21 wrote:
Hi, I have the height and range of projectile making a rectangle in x, y coordinate space. How should I figure out and draw the
projectile curve in that rectangular area at a certain angle of projection using GDI?You can draw line segments with MoveTo and LineTo (or with Polyline, if you want to be fancy). The trick now is to figure out which points the curve should pass through. Engage your Physics 101 skills for that.
Igor Tandetnik
 Marked as answer by Parcxs Monday, November 1, 2010 4:52 PM


David_21 wrote:
Thanks, but how would it be possible to draw or make it into a curved path? maybe if somehow I bend the line to make a curve from
the center point of range.A curve can be approximated arbitrarily closely with a sequence of short straight lines (the shorter the lines, the more accurate the approximation). If you calculate points on the curve every 10 pixels or so, and join them with straight lines, your eye won't notice the difference.
The display is a raster device consisting of a finite number of pixels. It can render arbirary curves only approximately. Take a sheet of graph paper; imagine that you are only allowed to completely fill some squares with pencil, while leaving others untouched. Try drawing a curve (any curve) under these conditions.
Igor Tandetnik
 Marked as answer by Parcxs Monday, November 1, 2010 4:52 PM
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David_21 wrote:
Hi, I have the height and range of projectile making a rectangle in x, y coordinate space. How should I figure out and draw the
projectile curve in that rectangular area at a certain angle of projection using GDI?You can draw line segments with MoveTo and LineTo (or with Polyline, if you want to be fancy). The trick now is to figure out which points the curve should pass through. Engage your Physics 101 skills for that.
Igor Tandetnik
 Marked as answer by Parcxs Monday, November 1, 2010 4:52 PM



David_21 wrote:
Thanks, but how would it be possible to draw or make it into a curved path? maybe if somehow I bend the line to make a curve from
the center point of range.A curve can be approximated arbitrarily closely with a sequence of short straight lines (the shorter the lines, the more accurate the approximation). If you calculate points on the curve every 10 pixels or so, and join them with straight lines, your eye won't notice the difference.
The display is a raster device consisting of a finite number of pixels. It can render arbirary curves only approximately. Take a sheet of graph paper; imagine that you are only allowed to completely fill some squares with pencil, while leaving others untouched. Try drawing a curve (any curve) under these conditions.
Igor Tandetnik
 Marked as answer by Parcxs Monday, November 1, 2010 4:52 PM