/// <summary>
/// Get the current or the first image and its rectangle
/// </summary>
private _ImageState GetImageState()
{
var states = _imageStates;
if (states == null)
{
return(null);
}
int index = _currentState;
if (index >= states.Length || states[index] == null)
{
index = 0;
}
_ImageState state = states[index];
int data = _baseData[index];
if ((data & State.MaskSizeDirty) != 0)
{
_baseData[index] = data & ~State.MaskSizeDirty;
RefreshDrawRect(state, (data & State.MaskResizeImage) != 0);
}
return(state);
}
/// <summary>
/// Set a state object at the specific index
/// </summary>
protected void SetState(int index, State state)
{
int data = state.GetData();
var imageStates = _imageStates;
var image = state.Image;
if (image != null)
{
_baseData[index] = data | State.MaskSizeDirty;
if (imageStates == null)
{
// create image states array
imageStates = _imageStates = index == 0 ?
new _ImageState[1] : new _ImageState[StateCount];
}
else if (index >= imageStates.Length)
{
// enlarge image states array
Array.Resize(ref imageStates, StateCount);
_imageStates = imageStates;
}
else if (imageStates[index] != null)
{
// set image
imageStates[index].image = image;
goto END_SET_STATE;
}
// create image state object
imageStates[index] = new _ImageState {
image = image
};
}
else
{
_baseData[index] = data;
if (imageStates != null && index < imageStates.Length && imageStates[index] != null)
{
imageStates[index].image = null;
}
}
END_SET_STATE:
// refresh the current state
if (index == _currentState)
{
Invalidate();
}
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
_ImageState imgState = GetImageState();
if (imgState == null || imgState.image == null)
{
return;
}
SetColorMatrix();
var img = imgState.image;
e.Graphics.DrawImage(img, imgState.area, 0, 0, img.Width, img.Height, GraphicsUnit.Pixel, _imgAttrs);
}
/// <summary>
/// Compute the rectangle of the image
/// </summary>
private void RefreshDrawRect(_ImageState state, bool resize)
{
Image image = state.image;
if (image == null)
{
return;
}
var pad = Padding;
int imgW = image.Width;
int imgH = image.Height;
int cW = Width - pad.Horizontal;
int cH = Height - pad.Vertical;
if (resize)
{
if (cW <= 0 || cH <= 0)
{
state.area = new Rectangle();
return;
}
double sw = (double)imgW / cW;
double sh = (double)imgH / cH;
if (sw < sh)
{
sw = sh;
}
imgW = (int)Math.Round(imgW / sw);
imgH = (int)Math.Round(imgH / sw);
}
state.area = new Rectangle(
pad.Left + (cW - imgW) / 2,
pad.Top + (cH - imgH) / 2,
imgW,
imgH
);
}
