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Grabbing the mouse cursor in GLFW


Grabbing the mouse cursor in GLFW

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Grabbing the mouse cursor in GLFW
Tag : cpp , By : Verbal
Date : November 24 2020, 05:47 AM


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Graphics32: Pan with mouse-drag, zoom to mouse cursor with mouse wheel


Tag : delphi , By : Bruce
Date : March 29 2020, 07:55 AM
will help you Graphics32 provides a component named TImgView32 which can zoom by setting the Scale property. The appropriate way to do so is by using the OnMouseWheelUp and -Down events. Set TabStop to True for triggering these events and set Centered to False. But scaling in this manner does not comply with your wish to center the zooming operation at the mouse cursor. So repositioning and resizing around that point is a nicer solution. Further, as I understand, the image is always aligned in the top-left corner of the component, so panning must also be accomplished by repositioning the component.
uses
  Windows, Classes, Controls, Forms, GR32_Image, GR32_Layers, Jpeg;

type
  TForm1 = class(TForm)
    ImgView: TImgView32;
    procedure FormCreate(Sender: TObject);
    procedure ImgViewMouseWheel(Sender: TObject; Shift: TShiftState;
      WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
    procedure ImgViewMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer; Layer: TCustomLayer);
    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
    procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    FDragging: Boolean;
    FFrom: TPoint;
  end;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  ImgView.Bitmap.LoadFromFile('D:\Pictures\Mona_Lisa.jpg');
  ImgView.TabStop := True;
  ImgView.ScrollBars.Visibility := svHidden;
  ImgView.ScaleMode := smResize;
end;

procedure TForm1.ImgViewMouseWheel(Sender: TObject; Shift: TShiftState;
  WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
const
  ZoomFactor: array[Boolean] of Single = (0.9, 1.1);
var
  R: TRect;
begin
  MousePos := ImgView.ScreenToClient(MousePos);
  with ImgView, MousePos do
    if PtInRect(ClientRect, MousePos) then
    begin
      R := BoundsRect;
      R.Left := Left + X - Round(ZoomFactor[WheelDelta > 0] * X);
      R.Top := Top + Y - Round(ZoomFactor[WheelDelta > 0] * Y);
      R.Right := R.Left + Round(ZoomFactor[WheelDelta > 0] * Width);
      R.Bottom := R.Top + Round(ZoomFactor[WheelDelta > 0] * Height);
      BoundsRect := R;
      Handled := True;
    end;
end;

procedure TForm1.ImgViewMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer; Layer: TCustomLayer);
begin
  FDragging := True;
  ImgView.Enabled := False; { Temporarily, to get MouseMove to the parent }
  FFrom := Point(X, Y);
end;

procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  if FDragging then
    ImgView.SetBounds(X - FFrom.X, Y - FFrom.Y, ImgView.Width, ImgView.Height);
end;

procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  FDragging := False;
  ImgView.Enabled := True;
  ImgView.SetFocus;
end;
uses
  Windows, Classes, Controls, Forms, Jpeg, ExtCtrls;

type
  TForm1 = class(TForm)
    Image: TImage;
    procedure FormCreate(Sender: TObject);
    procedure FormMouseWheel(Sender: TObject; Shift: TShiftState;
      WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
    procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure ImageDblClick(Sender: TObject);
    procedure ImageMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    FDragging: Boolean;
    FFrom: TPoint;
    FOrgImgBounds: TRect;
  end;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  DoubleBuffered := True;
  Image.Picture.LoadFromFile('D:\Pictures\Mona_Lisa.jpg');
  Image.Stretch := True;
  Image.Height := Round(Image.Width * Image.Picture.Height / Image.Picture.Width);
  FOrgImgBounds := Image.BoundsRect;
end;

procedure TForm1.FormMouseWheel(Sender: TObject; Shift: TShiftState;
  WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
const
  ZoomFactor: array[Boolean] of Single = (0.9, 1.1);
var
  R: TRect;
begin
  MousePos := Image.ScreenToClient(MousePos);
  with Image, MousePos do
    if PtInRect(ClientRect, MousePos) and ((WheelDelta > 0) and
      (Height < Self.ClientHeight) and (Width < Self.ClientWidth)) or
      ((WheelDelta < 0) and (Height > 20) and (Width > 20)) then
    begin
      R := BoundsRect;
      R.Left := Left + X - Round(ZoomFactor[WheelDelta > 0] * X);
      R.Top := Top + Y - Round(ZoomFactor[WheelDelta > 0] * Y);
      R.Right := R.Left + Round(ZoomFactor[WheelDelta > 0] * Width);
      R.Bottom := R.Top + Round(ZoomFactor[WheelDelta > 0] * Height);
      BoundsRect := R;
      Handled := True;
    end;
end;

procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  if FDragging then
    Image.SetBounds(X - FFrom.X, Y - FFrom.Y, Image.Width, Image.Height);
end;

procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Image.Enabled := True;
  FDragging := False;
end;

procedure TForm1.ImageDblClick(Sender: TObject);
begin
  Image.BoundsRect := FOrgImgBounds;
end;

procedure TForm1.ImageMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if not (ssDouble in Shift) then
  begin
    FDragging := True;
    Image.Enabled := False;
    FFrom := Point(X, Y);
    MouseCapture := True;
  end;
end;

Update mouse cursor without moving mouse with changed CSS cursor property


Tag : javascript , By : Gianluca Riccardi
Date : March 29 2020, 07:55 AM
hope this fix your issue you should check one of the answers given in the link that @rjmunro linked, it says:

GLFW mouse callback fired after mouse leave GLFWwindow?


Tag : cpp , By : todor
Date : March 29 2020, 07:55 AM
To fix the issue you can do I have figured out what the problem (or better put) issue is. On Windows the callback performs as expected where once the mouse leaves the windows area the callback stops firing. For OSX the window never loses focus and therefore the cursor callback is always being called. To fix the issue you simply have to test the coordinates to ensure that the mouse is in fact inside the window.

Hiding mouse cursor with glfw


Tag : cpp , By : IanM
Date : March 29 2020, 07:55 AM

How to fix GLFW cursor position value keep on getting bigger under GLFW_CURSOR_DISABLE?


Tag : opengl , By : apple
Date : March 29 2020, 07:55 AM
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