[英]Switch between Pan and Crop by button click C#
我正在使用WinForms。 在我的表單中,我有一個可以平移和裁剪的圖片框。 我的程序存在的問題是,我沒有單擊按鈕就可以在作物和平移之間切換的能力。 我怎樣才能做到這一點? 我在下面提供了我的代碼。
//------CROP::::::::::::::
int cropX;
int cropY;
int cropWidth;
int cropHeight;
public Pen cropPen;
//------PAN::::::::::::::::
private Point _pt;
private Point _pt2;
bool _isPanning = false;
Point startPt;
//-----Button on/off:::::::
private bool crop_btn_OFF = false;
private bool pan_btn_OFF = false;
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
_isPanning = true;
startPt = e.Location;
if (e.Button == System.Windows.Forms.MouseButtons.Left )
{
Cursor = Cursors.Cross;
cropX = e.X;
cropY = e.Y;
cropPen = new Pen(Color.FromArgb(153, 180, 209), 3);
cropPen.DashStyle = DashStyle.DashDotDot;
}
pictureBox1.Refresh();
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
//X and Y are the position of the crop
pictureBox1.Refresh();
cropWidth = e.X - cropX;
cropHeight = e.Y - cropY;
pictureBox1.CreateGraphics().DrawRectangle(cropPen, cropX, cropY, cropWidth, cropHeight);
}
//if (_isPanning) Un-comment this to Pan the image
//{
// Cursor = Cursors.SizeAll;
// Control c = (Control)sender;
// c.Left = (c.Left + e.X) - startPt.X;
// c.Top = (c.Top + e.Y) - startPt.Y;
// c.BringToFront();
//}
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
_isPanning = false;
Cursor = Cursors.Default;
}
private void btn_Crop_Click(object sender, EventArgs e)
{
crop_btn_OFF = true;
pan_btn_OFF = false;
if (cropWidth < 1)
{
return;
}
Rectangle rect = new Rectangle(cropX, cropY, cropWidth, cropHeight);
//First we define a rectangle with the help of already calculated points
Bitmap OriginalImage = new Bitmap(pictureBox1.Image, pictureBox1.Width, pictureBox1.Height);
//Original image
Bitmap _img = new Bitmap(cropWidth, cropHeight);
// for cropinf image
Graphics g = Graphics.FromImage(_img);
// create graphics
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
//set image attributes
g.DrawImage(OriginalImage, 0, 0, rect, GraphicsUnit.Pixel);
pictureBox1.Image = _img;
pictureBox1.Width = _img.Width;
pictureBox1.Height = _img.Height;
}
private void btn_Pan_Click(object sender, EventArgs e)
{
crop_btn_OFF = false;
pan_btn_OFF = true;
}
一個好主意是使用枚舉。 例如,這樣定義一個State
枚舉:
public enum State
{
Pan,
Crop
}
並包含一個字段
private State currentState;
單擊“平移”或“裁剪”按鈕時,將currentState設置為:
public void btnCrop_Click()
{
currentState = State.Crop;
}
public void btnPan_Click()
{
currentState = State.Pan;
}
在您的方法中,使用currentState字段指定應執行的操作
public void Foo()
{
if (currentState == State.Pan)
{
// Do Pan work
}
else if (currentState == State.Crop)
{
// Do Crop Work
}
}
如果我了解您要執行的操作,則需要使用名為pictureBox1_MouseDown的方法和名為pictureBox1_MouseMove的方法,以了解用戶是處於Pan模式還是Crop模式。 您已經通過定義名為_isPanning的變量開始了這個想法,但是您需要在我提到的方法中使用此數據。
希望我的回答能使您朝正確的方向前進。 我不願給出更具體的答案,因為有多種方法可以解決問題。
請仔細考慮單擊按鈕或拖動圖像時要發生的情況。 此刻,您的裁剪按鈕嘗試執行兩項操作:設置模式並應用裁剪。
嘗試更好地分離模式。 您的按鈕單擊處理程序應僅按照@Leigh的建議切換模式,鼠標處理程序應根據模式平移或裁剪。
我尚未測試您方法的內容,因此它們可能需要調試。 為了簡化操作,請在命名變量時遵循某種約定:例如,私有字段以下划線開頭,方法和屬性以大寫字母開頭,方法中的變量以小寫字母開頭。 我還在您的評論后添加了一些空格,因為尚不清楚它們是應用於前一行還是后一行。
private enum State
{
Pan,
Crop
}
private State _currentState;
public void btnCrop_Click()
{
_currentState = State.Crop;
}
public void btnPan_Click()
{
_currentState = State.Pan;
}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (_currentState == State.Crop)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left )
{
Cursor = Cursors.Cross;
_cropX = e.X;
_cropY = e.Y;
_cropPen = new Pen(Color.FromArgb(153, 180, 209), 3);
_cropPen.DashStyle = DashStyle.DashDotDot;
pictureBox1.Refresh();
}
}
else // state = pan
{
_isPanning = true;
_startPt = e.Location;
}
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (_currentState == State.Crop)
{
Cursor = Cursors.Cross;
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
//X and Y are the position of the crop
pictureBox1.Refresh();
_cropWidth = e.X - _cropX;
_cropHeight = e.Y - _cropY;
pictureBox1.CreateGraphics().DrawRectangle(_cropPen, _cropX, _cropY, _cropWidth, _cropHeight);
}
}
else // state = pan
if (_isPanning)
{
Cursor = Cursors.SizeAll;
Control c = (Control)sender;
c.Left = (c.Left + e.X) - _startPt.X;
c.Top = (c.Top + e.Y) - _startPt.Y;
c.BringToFront();
}
}
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
Cursor = Cursors.Default;
if (_currentState == State.Crop)
{
if (cropWidth < 1)
{
return;
}
Rectangle rect = new Rectangle(_cropX, _cropY, _cropWidth, _cropHeight);
//First we define a rectangle with the help of already calculated points
Bitmap originalImage = new Bitmap(pictureBox1.Image, pictureBox1.Width, pictureBox1.Height);
//Original image
Bitmap img = new Bitmap(_cropWidth, _cropHeight);
// for cropinf image
Graphics g = Graphics.FromImage(img);
// create graphics
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
//set image attributes
g.DrawImage(originalImage, 0, 0, rect, GraphicsUnit.Pixel);
pictureBox1.Image = img;
pictureBox1.Width = img.Width;
pictureBox1.Height = img.Height;
}
else // state = pan
{
// nothing to do here but leaving it for symmetry with the other methods
}
}
為了使功能對用戶更顯而易見,您可以將按鈕替換為單選按鈕,或者弄清楚如何使與當前狀態相對應的按鈕保持按下狀態。
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