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C# winforms - How to combine scrollbar with mouse wheel zooming?

Problem - I'm writing a program that draws graphics, and zooming is one of the features. Currently, a picturebox is placed on a panel, and the picturebox has vertical and horizontal scroll bars on the right and bottom. How to combine scrollbar with mouse wheel zooming? And I'm not sure if I should use paint to draw the graphics or set a bitmap to draw the graphics onto it?
Expected - When the mouse wheel is scrolled, the entire canvas(picturebox) include drawn graphics are scaled according to the current mouse position as the center (the horizontal and vertical scroll bars change according to the zoom center). When the mouse wheel is pressed and moved, the canvas can be dragged freely.
Expected as follows:
The initial code
private List<Point> _points;
private int _pointRadius = 50;
private float _scale = 1f;
private float _offsetX = 0f;
private float _offsetY = 0f;
private void picturebox_MouseDown(object sender, MouseEventArgs e)
{
_points.Add(e.Location);
}
private void picturebox_MouseWheel(object sender, MouseEvnetArgs e)
{
if(e.Delta < 0)
{
_scale += 0.1f;
_offsetX = e.X * (1f - _scale);
_offsetY = e.X * (1f - _scale);
}
else
{
_scale -= 0.1f;
_offsetX = e.X * (1f - _scale);
_offsetY = e.X * (1f - _scale);
}
picturebox.Invalidate();
}
private void picturebox_Paint(object sender, PaintEventArgs e)
{
e.Graphics.TranslateTransform(_offsetX, _offsetY);
e.Graphics.ScaleTransform(_scaleX, _scaleY);
foreach (Point p in _points)
{
e.Graphics.FillEllipse(Brushes.Black, p.X, - _pointRadius, p.Y - _pointRadius, 2 * _pointRadius, 2 * _pointRadius);
}
}
Hope the answer is modified based on the initial code.
Thanks in advance to everyone who helped me.

Would it be easier if I drew the graphics on a Bitmap?
Considering the nature of your task and the already implemented solutions in my ImageViewer I created a solution that draws the result in a Metafile, which is both elegant, consumes minimal memory and allows zooming without quality issues.
Here is the stripped version of my ImageViewer:
public class MetafileViewer : Control
{
private HScrollBar sbHorizontal = new HScrollBar { Visible = false };
private VScrollBar sbVertical = new VScrollBar { Visible = false };
private Metafile? image;
private Size imageSize;
private Rectangle targetRectangle;
private Rectangle clientRectangle;
private float zoom = 1;
private bool sbHorizontalVisible;
private bool sbVerticalVisible;
private int scrollFractionVertical;
public MetafileViewer()
{
Controls.AddRange(new Control[] { sbHorizontal, sbVertical });
sbHorizontal.ValueChanged += ScrollbarValueChanged;
sbVertical.ValueChanged += ScrollbarValueChanged;
}
void ScrollbarValueChanged(object? sender, EventArgs e) => Invalidate();
public Metafile? Image
{
get => image;
set
{
image = value;
imageSize = image?.Size ?? default;
InvalidateLayout();
}
}
public bool TryTranslate(Point mouseCoord, out PointF canvasCoord)
{
canvasCoord = default;
if (!targetRectangle.Contains(mouseCoord))
return false;
canvasCoord = new PointF((mouseCoord.X - targetRectangle.X) / zoom, (mouseCoord.Y - targetRectangle.Y) / zoom);
if (sbHorizontalVisible)
canvasCoord.X += sbHorizontal.Value / zoom;
if (sbVerticalVisible)
canvasCoord.Y += sbVertical.Value / zoom;
return true;
}
private void InvalidateLayout()
{
Invalidate();
if (imageSize.IsEmpty)
{
sbHorizontal.Visible = sbVertical.Visible = sbHorizontalVisible = sbVerticalVisible = false;
targetRectangle = Rectangle.Empty;
return;
}
Size clientSize = ClientSize;
if (clientSize.Width < 1 || clientSize.Height < 1)
{
targetRectangle = Rectangle.Empty;
return;
}
Size scaledSize = imageSize.Scale(zoom);
// scrollbars visibility
sbHorizontalVisible = scaledSize.Width > clientSize.Width
|| scaledSize.Width > clientSize.Width - SystemInformation.VerticalScrollBarWidth && scaledSize.Height > clientSize.Height;
sbVerticalVisible = scaledSize.Height > clientSize.Height
|| scaledSize.Height > clientSize.Height - SystemInformation.HorizontalScrollBarHeight && scaledSize.Width > clientSize.Width;
if (sbHorizontalVisible)
clientSize.Height -= SystemInformation.HorizontalScrollBarHeight;
if (sbVerticalVisible)
clientSize.Width -= SystemInformation.VerticalScrollBarWidth;
if (clientSize.Width < 1 || clientSize.Height < 1)
{
targetRectangle = Rectangle.Empty;
return;
}
Point clientLocation = Point.Empty;
var targetLocation = new Point((clientSize.Width >> 1) - (scaledSize.Width >> 1),
(clientSize.Height >> 1) - (scaledSize.Height >> 1));
// both scrollbars
if (sbHorizontalVisible && sbVerticalVisible)
{
sbHorizontal.Dock = sbVertical.Dock = DockStyle.None;
sbHorizontal.Width = clientSize.Width;
sbHorizontal.Top = clientSize.Height;
sbHorizontal.Left = 0;
sbVertical.Height = clientSize.Height;
sbVertical.Left = clientSize.Width;
}
// horizontal scrollbar
else if (sbHorizontalVisible)
sbHorizontal.Dock = DockStyle.Bottom;
// vertical scrollbar
else if (sbVerticalVisible)
sbVertical.Dock = DockStyle.Right;
// adjust scrollbar values
if (sbHorizontalVisible)
{
sbHorizontal.Minimum = targetLocation.X;
sbHorizontal.Maximum = targetLocation.X + scaledSize.Width;
sbHorizontal.LargeChange = clientSize.Width;
sbHorizontal.SmallChange = 32;
sbHorizontal.Value = Math.Min(sbHorizontal.Value, sbHorizontal.Maximum - sbHorizontal.LargeChange);
}
if (sbVerticalVisible)
{
sbVertical.Minimum = targetLocation.Y;
sbVertical.Maximum = targetLocation.Y + scaledSize.Height;
sbVertical.LargeChange = clientSize.Height;
sbVertical.SmallChange = 32;
sbVertical.Value = Math.Min(sbVertical.Value, sbVertical.Maximum - sbVertical.LargeChange);
}
sbHorizontal.Visible = sbHorizontalVisible;
sbVertical.Visible = sbVerticalVisible;
clientRectangle = new Rectangle(clientLocation, clientSize);
targetRectangle = new Rectangle(targetLocation, scaledSize);
if (sbVerticalVisible)
clientRectangle.X = SystemInformation.VerticalScrollBarWidth;
}
protected override void OnSizeChanged(EventArgs e)
{
base.OnSizeChanged(e);
InvalidateLayout();
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
if (image == null || e.ClipRectangle.Width <= 0 || e.ClipRectangle.Height <= 0)
return;
if (targetRectangle.IsEmpty)
InvalidateLayout();
if (targetRectangle.IsEmpty)
return;
Graphics g = e.Graphics;
g.IntersectClip(clientRectangle);
Rectangle dest = targetRectangle;
if (sbHorizontalVisible)
dest.X -= sbHorizontal.Value;
if (sbVerticalVisible)
dest.Y -= sbVertical.Value;
g.DrawImage(image, dest);
g.DrawRectangle(SystemPens.ControlText, Rectangle.Inflate(targetRectangle, 1, 1));
}
protected override void OnMouseWheel(MouseEventArgs e)
{
base.OnMouseWheel(e);
switch (ModifierKeys)
{
// zoom
case Keys.Control:
float delta = (float)e.Delta / SystemInformation.MouseWheelScrollDelta / 5;
if (delta.Equals(0f))
return;
delta += 1;
SetZoom(zoom * delta);
break;
// vertical scroll
case Keys.None:
VerticalScroll(e.Delta);
break;
}
}
private void VerticalScroll(int delta)
{
// When scrolling by mouse, delta is always +-120 so this will be a small change on the scrollbar.
// But we collect the fractional changes caused by the touchpad scrolling so it will not be lost either.
int totalDelta = scrollFractionVertical + delta * sbVertical.SmallChange;
scrollFractionVertical = totalDelta % SystemInformation.MouseWheelScrollDelta;
int newValue = sbVertical.Value - totalDelta / SystemInformation.MouseWheelScrollDelta;
SetValueSafe(sbVertical, newValue);
}
internal static void SetValueSafe(ScrollBar scrollBar, int value)
{
if (value < scrollBar.Minimum)
value = scrollBar.Minimum;
else if (value > scrollBar.Maximum - scrollBar.LargeChange + 1)
value = scrollBar.Maximum - scrollBar.LargeChange + 1;
scrollBar.Value = value;
}
private void SetZoom(float value)
{
const float maxZoom = 10f;
float minZoom = image == null ? 1f : 1f / Math.Min(imageSize.Width, imageSize.Height);
if (value < minZoom)
value = minZoom;
if (value > maxZoom)
value = maxZoom;
if (zoom.Equals(value))
return;
zoom = value;
InvalidateLayout();
}
}
And then the updated version of your initial code (add a new point by right click, zoom by Ctrl + mouse scroll):
public partial class RenderMetafileForm : Form
{
private static Size canvasSize = new Size(300, 200);
private List<PointF> points = new List<PointF>();
private const float pointRadius = 5;
public RenderMetafileForm()
{
InitializeComponent();
metafileViewer.MouseClick += MetafileViewer_MouseClick;
UpdateMetafile();
}
private void MetafileViewer_MouseClick(object? sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Right && metafileViewer.TryTranslate(e.Location, out var coord))
{
points.Add(coord);
UpdateMetafile();
}
}
private void UpdateMetafile()
{
Graphics refGraph = Graphics.FromHwnd(IntPtr.Zero);
IntPtr hdc = refGraph.GetHdc();
Metafile result;
try
{
result = new Metafile(hdc, new Rectangle(Point.Empty, canvasSize), MetafileFrameUnit.Pixel, EmfType.EmfOnly, "Canvas");
using (var g = Graphics.FromImage(result))
{
foreach (PointF point in points)
g.FillEllipse(Brushes.Navy, point.X - pointRadius, point.Y - pointRadius, pointRadius * 2, pointRadius * 2);
}
}
finally
{
refGraph.ReleaseHdc(hdc);
refGraph.Dispose();
}
Metafile? previous = metafileViewer.Image;
metafileViewer.Image = result;
previous?.Dispose();
}
}
Result:
⚠️ Note: I did not add panning by keyboard or by grabbing the image but you can extract those from the original ImageViewer. Also, I removed DPI-aware scaling but see the ScaleSize extensions in the linked project.

Move the zoomed image by gyroscope in xamarin

I want to move the zoomed image with gyroscope. As you can see in below code I can do this thing by hand and I got a good result. I have to write something inside "Gyroscope_ReadingChanged" to convert gyroscope data to the Content.TranslationX and Content.TranslationY. Any help would be appreciated.
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:video="clr-namespace:UbSports.Controls"
xmlns:local="clr-namespace:UbSports.Controls"
x:Class="UbSports.Pages.TestPage">
<local:PinchToZoomContainer VerticalOptions="FillAndExpand">
<local:PinchToZoomContainer.Content>
<Image x:Name="image" Source="waterfront.jpg" />
</local:PinchToZoomContainer.Content>
</local:PinchToZoomContainer>
</ContentPage>
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class TestPage: ContentPage
{
public TestPage()
{
InitializeComponent();
}
}
public class PinchToZoomContainer : ContentView
{
public PinchToZoomContainer()
{
Gyroscope.ReadingChanged += Gyroscope_ReadingChanged;
try
{
Gyroscope.Start(SensorSpeed.UI);
}
catch (FeatureNotSupportedException fnsEx)
{
}
catch (Exception ex)
{
}
var panGesture = new PanGestureRecognizer();
panGesture.PanUpdated += OnPanUpdated;
GestureRecognizers.Add(panGesture);
var pinchGesture = new PinchGestureRecognizer();
pinchGesture.PinchUpdated += OnPinchUpdated;
GestureRecognizers.Add(pinchGesture);
}
void Gyroscope_ReadingChanged(object sender, GyroscopeChangedEventArgs e)
{
var data = e.Reading;
if (data.AngularVelocity.X == 0 && data.AngularVelocity.Y == 0) return;
// do something
}
void OnPanUpdated(object sender, PanUpdatedEventArgs e)
{
switch (e.StatusType)
{
case GestureStatus.Started:
startX = e.TotalX;
startY = e.TotalY;
Content.AnchorX = 0;
Content.AnchorY = 0;
break;
case GestureStatus.Running:
var maxTranslationX = Content.Scale * Content.Width - Content.Width;
Content.TranslationX = Math.Min(0, Math.Max(-maxTranslationX, xOffset + e.TotalX - startX));
var maxTranslationY = Content.Scale * Content.Height - Content.Height;
Content.TranslationY = Math.Min(0, Math.Max(-maxTranslationY, yOffset + e.TotalY - startY));
break;
case GestureStatus.Completed:
xOffset = Content.TranslationX;
yOffset = Content.TranslationY;
break;
}
}
void OnPinchUpdated(object sender, PinchGestureUpdatedEventArgs e)
{
if (e.Status == GestureStatus.Started)
{
startScale = Content.Scale;
Content.AnchorX = 0;
Content.AnchorY = 0;
}
if (e.Status == GestureStatus.Running)
{
currentScale += (e.Scale - 1) * startScale;
currentScale = Math.Max(1, currentScale);
double renderedX = Content.X + xOffset;
double deltaX = renderedX / Width;
double deltaWidth = Width / (Content.Width * startScale);
double originX = (e.ScaleOrigin.X - deltaX) * deltaWidth;
double renderedY = Content.Y + yOffset;
double deltaY = renderedY / Height;
double deltaHeight = Height / (Content.Height * startScale);
double originY = (e.ScaleOrigin.Y - deltaY) * deltaHeight;
double targetX = xOffset - (originX * Content.Width) * (currentScale - startScale);
double targetY = yOffset - (originY * Content.Height) * (currentScale - startScale);
Content.TranslationX = targetX.Clamp(-Content.Width * (currentScale - 1), 0);
Content.TranslationY = targetY.Clamp(-Content.Height * (currentScale - 1), 0);
Content.Scale = currentScale;
}
if (e.Status == GestureStatus.Completed)
{
xOffset = Content.TranslationX;
yOffset = Content.TranslationY;
}
}
}

How I can zoom in & zoom out images and move all images

I display the images on canvas and I want to be able to move all the images. Currently I am only able to move the last image which I brought on canvas. I also want to be able to zoom these images. Please help me in this.
private TranslateTransform dragTranslation;
// Constructor
void Drag_ManipulationDelta(object sender,ManipulationDeltaRoutedEventArgs e)
{
// Move the rectangle.
dragTranslation.X += e.Delta.Translation.X;
dragTranslation.Y += e.Delta.Translation.Y;
}
private void Stickers1_SelectionChanged(object sender,SelectionChangedEventArgs e)
{
var selecteditem = e.AddedItems[0] as StickersImageListModel;
Stickers1.Visibility = Visibility.Collapsed;
Image imageitem = new Image();
BitmapImage image = new BitmapImage(new System.Uri(selecteditem.Imageurl, UriKind.Absolute));
imageitem.Source = image;
my_canvas.Children.Add(imageitem);
imageitem.AllowDrop = true;
imageitem.ManipulationMode = ManipulationModes.All;
imageitem.ManipulationDelta += Drag_ManipulationDelta;
dragTranslation = new TranslateTransform();
imageitem.RenderTransform = this.dragTranslation;
var st = (ScaleTransform)imageitem.RenderTransform;
double zoom = e.Delta > 0 ? .2 : -.2;
st.ScaleX += zoom;
st.ScaleY += zoom;
my_canvas.Visibility = Visibility.Visible;
}

You dont have to use dragTranslation property
void Drag_ManipulationDelta(object sender,ManipulationDeltaRoutedEventArgs e)
{
// Move the rectangle.
Image img = sender as Image;
CompositeTransform ct = img.RenderTransform as CompositeTransform;
ct.ScaleX *= e.Delta.Scale;
ct.ScaleY *= e.Delta.Scale;
if (ct.ScaleX < 1.0) ct.ScaleX = 1.0;
if (ct.ScaleY < 1.0) ct.ScaleY = 1.0;
if (ct.ScaleX > 4.0) ct.ScaleX = 4.0;
if (ct.ScaleY > 4.0) ct.ScaleY = 4.0;
//Checking with canvas boundary so that image wont go behind canvas
if ((ct.TranslateX + e.Delta.Translation.X) <= (mycanvas.ActualWidth - img.ActualWidth) && ct.TranslateX + e.Delta.Translation.X>=0)
ct.TranslateX += e.Delta.Translation.X;
if ((ct.TranslateY + e.Delta.Translation.Y) <= (mycanvas.ActualHeight - img.ActualHeight) && ct.TranslateY + e.Delta.Translation.Y >= 0)
ct.TranslateY += e.Delta.Translation.Y;
}
private void Stickers1_SelectionChanged(object sender,SelectionChangedEventArgs e)
{
...
//Using CompositeTransform instead of TranslateTransform
CompositeTransform ct = new CompositeTransform();
imageitem.RenderTransform = ct;
}

Picturebox zooming works on preloaded image but not graphics (C#/Winforms)

I have a picturebox that I want the user of my winform to be able to interact with by zooming and dragging the image. Right now that form looks like this
I have the drag and zoom methods implemented. Those look like this.
private void pictureBox1_MouseWheel(object sender, MouseEventArgs e)
{
// If the mouse wheel is moved forward (Zoom in)
if (e.Delta > 0)
{
// Change the size of the picturebox, multiply it by the ZOOMFACTOR
pictureBox1.Width = (int)(pictureBox1.Width * 1.25);
pictureBox1.Height = (int)(pictureBox1.Height * 1.25);
// Formula to move the picturebox, to zoom in the point selected by the mouse cursor
pictureBox1.Top = (int)(e.Y - 1.25 * (e.Y - pictureBox1.Top));
pictureBox1.Left = (int)(e.X - 1.25 * (e.X - pictureBox1.Left));
}
else
{
pictureBox1.Width = (int)(pictureBox1.Width / 1.25);
pictureBox1.Height = (int)(pictureBox1.Height / 1.25);
// Formula to move the picturebox, to zoom in the point selected by the mouse cursor
pictureBox1.Top = (int)(e.Y - 0.80 * (e.Y - pictureBox1.Top));
pictureBox1.Left = (int)(e.X - 0.80 * (e.X - pictureBox1.Left));
}
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
dragging = false;
Console.WriteLine("Dragging: false");
}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
dragging = true;
xDrag = e.X;
yDrag = e.Y;
Console.WriteLine("Dragging: true");
}
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
Control c = sender as Control;
if (dragging && c != null)
{
c.Top = e.Y + c.Top - yDrag;
c.Left = e.X + c.Left - xDrag;
Console.WriteLine(e.Location.ToString());
}
}
The dragging works fine but the zooming does not work as expected. Instead of zooming in it pushes the image up and to the left as I "zoom in"
Out of curiousity I loaded a bitmap I saved off Google in to test the zoom and it works fine with bitmap images from files; it just doesn't work with images drawn with the Graphics object and I have no idea why. Any help would be greatly appreciated.
Paint event code for picturebox
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
RunEntry entry = this.passedHistory.SelectedItem as RunEntry;
if (entry == null)
{
return;
}
else if(entry.FileRead != null && checkBox1.Checked) //If ANS is selected and show all, get TRE
{
foreach(RunEntry r in passedHistory.Items)
{
if (r.TreComponentRead != null)
{
string ansName = Path.GetFileNameWithoutExtension(entry.FileName);
string treName = Path.GetFileNameWithoutExtension(r.FileName);
if(ansName.Equals(treName, StringComparison.OrdinalIgnoreCase))
{
entry.TreComponentRead = r.TreComponentRead;
}
}
}
}
if (isDraw && entry.FileRead != null)
{
//Preparing to draw
Graphics g = e.Graphics;
g.ScaleTransform(2f, 2f);
g.SmoothingMode = SmoothingMode.AntiAlias;
g.InterpolationMode = InterpolationMode.Bicubic;
AnsFile objToDraw = entry.FileRead;
Pen pen = new Pen(Color.Black);
//Getting size of bitmap
int maxWidth = 0, maxHeight = 0;
foreach (AnsJoint joint in objToDraw.AnsJoints)
{
if (joint.Location.X.Length > maxWidth)
{
maxWidth = (int)joint.Location.X.Length;
}
if (joint.Location.Y.Length > maxHeight)
{
maxHeight = (int)joint.Location.Y.Length;
}
}
//Drawing joints //TODO: (Trello: Improve math behind visualizer)
foreach (AnsJoint joint in objToDraw.AnsJoints)
{
PointF jointPoint = this.ToCartesian(new PointF((float)joint.Location.X.Length - 4f, (float)joint.Location.Y.Length + 10f), maxHeight);
e.Graphics.DrawString(joint.JointID.ToString(), new Font(FontFamily.GenericMonospace, 6f, FontStyle.Regular, GraphicsUnit.Point, 1, false), Brushes.Black, jointPoint);
}
//Draw the panels and links //TODO: (Trello: Improve math behind visualizer)
foreach (AnsMember member in objToDraw.AnsMembers)
{
List<AnsPanel> panels = member.Panels; //Drawing the panels
foreach (AnsPanel pan in panels)
{
pen.Color = Color.Red;
PointF p1 = this.ToCartesian(new PointF((float)pan.I.Location.X.Length, (float)pan.I.Location.Y.Length), maxHeight);
PointF p2 = this.ToCartesian(new PointF((float)pan.J.Location.X.Length, (float)pan.J.Location.Y.Length), maxHeight);
g.DrawEllipse(pen, p1.X - 2.5f, p1.Y - 2.5f, 5, 5);
g.DrawEllipse(pen, p2.X - 2.5f, p2.Y - 2.5f, 5, 5);
g.DrawEllipse(pen, p1.X - 3, p1.Y - 3.3f, 5, 5);
g.DrawEllipse(pen, p2.X - 3, p2.Y - 3.3f, 5, 5);
pen.Color = Color.Black;
g.DrawLine(pen, p1, p2);
}
List<AnsLink> links = member.Links; //Drawing the links
foreach (AnsLink link in links)
{
PointF p1 = this.ToCartesian(new PointF((float)link.I.Location.X.Length, (float)link.I.Location.Y.Length), maxHeight);
PointF p2 = this.ToCartesian(new PointF((float)link.J.Location.X.Length, (float)link.J.Location.Y.Length), maxHeight);
g.FillEllipse(Brushes.Green, p1.X - 1.5f, p1.Y - 1.5f, 3, 3);
g.FillEllipse(Brushes.Green, p2.X - 1.5f, p2.Y - 1.5f, 3, 3);
g.DrawLine(pen, p1, p2);
}
}
pictureBox1.Tag = entry.FileName;
}
if (isDraw && entry.TreComponentRead != null)
{
//Preparing to draw
Graphics g = e.Graphics;
g.ScaleTransform(2f, 2f);
g.SmoothingMode = SmoothingMode.AntiAlias;
g.InterpolationMode = InterpolationMode.Bicubic;
TreComponent objToDraw = entry.TreComponentRead;
Pen pen = new Pen(Color.Black);
int maxWidth = 0, maxHeight = 0;
foreach (Member member in objToDraw.Members)
{
foreach (GeometryClassLibrary.Point p in member.Geometry.Vertices)
{
if (p.X.Inches > maxWidth)
{
maxWidth = (int)p.X.Inches;
}
if (p.Y.Inches > maxHeight)
{
maxHeight = (int)p.Y.Inches;
}
}
}
maxHeight += 5; maxWidth += 5;
maxHeight += 15; maxWidth += 5;
foreach (Member member in objToDraw.Members)
{
List<PointF> pointsToDraw = new List<PointF>();
foreach (GeometryClassLibrary.Point p in member.Geometry.Vertices)
{
pointsToDraw.Add(ToCartesian(new PointF((float)p.X.Inches, (float)p.Y.Inches), maxHeight));
PointF pointToDraw = this.ToCartesian(new PointF((float)p.X.Inches, (float)p.Y.Inches), maxHeight);
g.FillEllipse(Brushes.Red, pointToDraw.X - 1.5f, pointToDraw.Y - 1.5f, 3, 3);
pointsToDraw.Add(pointToDraw);
}
g.DrawPolygon(pen, pointsToDraw.ToArray());
//Getting center of member and labeling member
float totalX = 0, totalY = 0;
foreach (PointF p in pointsToDraw)
{
totalX += p.X;
totalY += p.Y;
}
float centerX = totalX / pointsToDraw.Count;
float centerY = totalY / pointsToDraw.Count - 10;
PointF midPoint = new PointF(centerX, centerY);
g.DrawString(member.Name, new Font(FontFamily.GenericMonospace, 6f, FontStyle.Regular, GraphicsUnit.Point, 1, false), Brushes.Black, midPoint);
}
pictureBox1.Tag = entry.FileName;
}
}

How to find the coordinates of the mouse in the background image winform c#

I have a BufferedGraphics painted in the panel. The image is zoomed in and zoomed out. From this buffered graphic images how can i find the mouse position in the image not in the panel.
private void panel2_paint(object sender, PaintEventArgs e)
{
if (bitmap != null)
{
float widthZoomed = panel2.Width / Zoom;
float heigthZoomed = panel2.Height / Zoom;
if (widthZoomed > 30000.0f)
{
Zoom = panel2.Width / 30000.0f;
widthZoomed = 30000.0f;
}
if (heigthZoomed > 30000.0f)
{
Zoom = panel2.Height / 30000.0f;
heigthZoomed = 30000.0f;
}
if (widthZoomed < 2.0f)
{
Zoom = panel2.Width / 2.0f;
widthZoomed = 2.0f;
}
if (heigthZoomed < 2.0f)
{
Zoom = panel2.Height / 2.0f;
heigthZoomed = 2.0f;
}
float wz2 = widthZoomed / 2.0f;
float hz2 = heigthZoomed / 2.0f;
Rectangle drawRect = new Rectangle(
(int)(viewPortCenter.X - wz2),
(int)(viewPortCenter.Y - hz2),
(int)(widthZoomed),
(int)(heigthZoomed));
drawrecX = drawRect.X;
drawrecY = drawRect.Y;
dispwidth = (int)(widthZoomed);
dispheight = (int)(heigthZoomed);
myBuffer.Graphics.Clear(Color.White); //Clear the Back buffer
Console.WriteLine(this.panel2.DisplayRectangle.Width);
Console.WriteLine(this.panel2.DisplayRectangle.Height);
myBuffer.Graphics.DrawImage(bitmap, this.panel2.DisplayRectangle, drawRect, GraphicsUnit.Pixel);
//pictureBox1.Image =
myBuffer.Render(this.panel2.CreateGraphics());
//this.toolStripStatusLabel1.Text = "Zoom: " + ((int)(this.Zoom * 100)).ToString() + "%";
}
}
the above code is the paint part.
To find the location of the mouse in the image i tried like this
private void panel2_DoubleClick(object sender, EventArgs e)
{
var mouseArgs = (MouseEventArgs)e;
double Pic_width = dispwidth / panel2.Width;//to find the relative position
double Pic_height = dispheight / panel2.Height;
int xpoint = (int)Pic_width * mouseArgs.X + drawrecX;//drawrecX is the X coordinate from the drawing image
int ypoint = (int)Pic_height * mouseArgs.Y + drawrecY;
}
but this code does not give me the exact position. any idea?

Try this:
private void panel2_DoubleClick(object sender, EventArgs e)
{
var mouseArgs = (MouseEventArgs)e;
int x = mouseArgs.X - drawrecX;
int y = mouseArgs.Y - drawrecY;
var size = ImageSizeWithoutZoom;
var zoomSize = ImageSizeWithZoom;
double xPoint = x * size.X / zoomSize.X;
double yPoint = y * size.Y / zoomSize.Y;
}