private void CalcCoordsAndUpdate(ColourHandler.HSV HSV)
{
// Convert color to real-world coordinates and then calculate
// the various points. HSV.Hue represents the degrees (0 to 360),
// HSV.Saturation represents the radius.
// This procedure doesn't draw anything--it simply
// updates class-level variables. The UpdateDisplay
// procedure uses these values to update the screen.
// Given the angle (HSV.Hue), and distance from
// the center (HSV.Saturation), and the center,
// calculate the point corresponding to
// the selected color, on the color wheel.
colorPoint = GetPoint((double)HSV.Hue / 255 * 360,
(double)HSV.Saturation / 255 * radius,
centerPoint);
// Given the brightness (HSV.value), calculate the
// point corresponding to the brightness indicator.
brightnessPoint = CalcBrightnessPoint(HSV.value);
// Store information about the selected color.
brightness = HSV.value;
selectedColor = ColourHandler.HSVtoColour(HSV);
RGB = ColourHandler.HSVtoRGB(HSV);
// The full color is the same as HSV, except that the
// brightness is set to full (255). This is the top-most
// color in the brightness gradient.
fullColor = ColourHandler.HSVtoColour(HSV.Hue, HSV.Saturation, 255);
}
public void Draw(Graphics g, Point mousePoint)
{
// You've moved the mouse.
// Now update the screen to match.
double distance;
int degrees;
Point delta;
Point newColorPoint;
Point newBrightnessPoint;
Point newPoint;
// Keep track of the previous color pointer point,
// so you can put the mouse there in case the
// user has clicked outside the circle.
newColorPoint = colorPoint;
newBrightnessPoint = brightnessPoint;
// Store this away for later use.
this.g = g;
if (currentState == MouseState.MouseUp)
{
if (!mousePoint.IsEmpty)
{
if (colourRegion.IsVisible(mousePoint))
{
// Is the mouse point within the color circle?
// If so, you just clicked on the color wheel.
currentState = MouseState.ClickOnColour;
}
else if (brightnessRegion.IsVisible(mousePoint))
{
// Is the mouse point within the brightness area?
// You clicked on the brightness area.
currentState = MouseState.ClickOnBrightness;
}
else
{
// Clicked outside the color and the brightness
// regions. In that case, just put the
// pointers back where they were.
currentState = MouseState.ClickOutsideRegion;
}
}
}
switch (currentState)
{
case MouseState.ClickOnBrightness:
case MouseState.DragInBrightness:
// Calculate new color information
// based on the brightness, which may have changed.
newPoint = mousePoint;
if (newPoint.Y < brightnessMin)
{
newPoint.Y = brightnessMin;
}
else if (newPoint.Y > brightnessMax)
{
newPoint.Y = brightnessMax;
}
newBrightnessPoint = new Point(brightnessX, newPoint.Y);
brightness = (int)((brightnessMax - newPoint.Y) * brightnessScaling);
HSV.value = brightness;
RGB = ColourHandler.HSVtoRGB(HSV);
break;
case MouseState.ClickOnColour:
case MouseState.DragInColour:
// Calculate new color information
// based on selected color, which may have changed.
newColorPoint = mousePoint;
// Calculate x and y distance from the center,
// and then calculate the angle corresponding to the
// new location.
delta = new Point(
mousePoint.X - centerPoint.X, mousePoint.Y - centerPoint.Y);
degrees = CalcDegrees(delta);
// Calculate distance from the center to the new point
// as a fraction of the radius. Use your old friend,
// the Pythagorean theorem, to calculate this value.
distance = Math.Sqrt(delta.X * delta.X + delta.Y * delta.Y) / radius;
if (currentState == MouseState.DragInColour)
{
if (distance > 1)
{
// Mouse is down, and outside the circle, but you
// were previously dragging in the color circle.
// What to do?
// In that case, move the point to the edge of the
// circle at the correct angle.
distance = 1;
newColorPoint = GetPoint(degrees, radius, centerPoint);
}
}
// Calculate the new HSV and RGB values.
HSV.Hue = (int)(degrees * 255 / 360);
HSV.Saturation = (int)(distance * 255);
HSV.value = brightness;
RGB = ColourHandler.HSVtoRGB(HSV);
fullColor = ColourHandler.HSVtoColour(HSV.Hue, HSV.Saturation, 255);
break;
}
selectedColor = ColourHandler.HSVtoColour(HSV);
// Raise an event back to the parent form,
// so the form can update any UI it's using
// to display selected color values.
OnColourChanged(RGB, HSV);
// On the way out, set the new state.
switch (currentState)
{
case MouseState.ClickOnBrightness:
currentState = MouseState.DragInBrightness;
break;
case MouseState.ClickOnColour:
currentState = MouseState.DragInColour;
break;
case MouseState.ClickOutsideRegion:
currentState = MouseState.DragOutsideRegion;
break;
}
// Store away the current points for next time.
colorPoint = newColorPoint;
brightnessPoint = newBrightnessPoint;
// Draw the gradients and points.
UpdateDisplay();
}