[英]Switch between Pan and Crop by button click C#
我正在使用WinForms。 在我的表单中,我有一个可以平移和裁剪的图片框。 我的程序存在的问题是,我没有单击按钮就可以在作物和平移之间切换的能力。 我怎样才能做到这一点? 我在下面提供了我的代码。
//------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;
}
一个好主意是使用枚举。 例如,这样定义一个State
枚举:
public enum State
{
Pan,
Crop
}
并包含一个字段
private State currentState;
单击“平移”或“裁剪”按钮时,将currentState设置为:
public void btnCrop_Click()
{
currentState = State.Crop;
}
public void btnPan_Click()
{
currentState = State.Pan;
}
在您的方法中,使用currentState字段指定应执行的操作
public void Foo()
{
if (currentState == State.Pan)
{
// Do Pan work
}
else if (currentState == State.Crop)
{
// Do Crop Work
}
}
如果我了解您要执行的操作,则需要使用名为pictureBox1_MouseDown的方法和名为pictureBox1_MouseMove的方法,以了解用户是处于Pan模式还是Crop模式。 您已经通过定义名为_isPanning的变量开始了这个想法,但是您需要在我提到的方法中使用此数据。
希望我的回答能使您朝正确的方向前进。 我不愿给出更具体的答案,因为有多种方法可以解决问题。
请仔细考虑单击按钮或拖动图像时要发生的情况。 此刻,您的裁剪按钮尝试执行两项操作:设置模式并应用裁剪。
尝试更好地分离模式。 您的按钮单击处理程序应仅按照@Leigh的建议切换模式,鼠标处理程序应根据模式平移或裁剪。
我尚未测试您方法的内容,因此它们可能需要调试。 为了简化操作,请在命名变量时遵循某种约定:例如,私有字段以下划线开头,方法和属性以大写字母开头,方法中的变量以小写字母开头。 我还在您的评论后添加了一些空格,因为尚不清楚它们是应用于前一行还是后一行。
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
}
}
为了使功能对用户更显而易见,您可以将按钮替换为单选按钮,或者弄清楚如何使与当前状态相对应的按钮保持按下状态。
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