# RotatedRectangle API¶

Note

For an overview of the ScanImage® Roi concept, please review the page Scanfields, ROIs, ROI Groups.

For an overview of the RoiGroup and Roi API, please review the article RoiGroup & Roi API

## Rotated Rectangle Imaging Scanfield¶

For imaging with a rectangular scanpattern, ScanImage® uses the Scanfield ‘RotatedRectangle’. The following paramters define this Scanfield:

```Rotated Rectangle Imaging Scanfield
hSf = scanimage.mroi.scanfield.fields.RotatedRectangle();  % create an Imaging Scanfield of type RotatedRectangle
hSf.pixelResolutionXY = [512,512];                         % set [x,y] resolution
hSf.centerXY = [0.5,0.5];                                  % set [x,y] center (in reference coordinate space)
hSf.sizeXY = [0.5 0.5];                                    % set [x,y] size (in reference coordinate space)
hSf.rotationDegrees= 0;                                    % set rotation (in reference coordinate space)
```

## Pixel Positions in Reference Space¶

Note

Review the ScanImage® Coordinate Systems page to learn more about the different coordinate spaces used in ScanImage.

Scanfields of type RotatedRectangle have two associated affine matrices that allow coordinate space conversions

 pixelToRefTransfrom transform pixel coordinates to reference space affine transform scanfield coordinates to reference space

Pixel To Reference Space Transform

```hSf = scanimage.mroi.scanfield.fields.RotatedRectangle();  % create an Imaging Scanfield of type RotatedRectangle
hSf.pixelResolutionXY = [32,32];                           % set [x,y] resolution
hSf.centerXY = [0.5,0.5];                                  % set [x,y] resolution
hSf.sizeXY = [0.5,0.5];                                    % set [x,y] center (in reference coordinate space)
hSf.rotationDegrees = 20;                                  % set [x,y] size (in reference coordinate space)
pixToRefT = hSf.pixelToRefTransform();                     % get affine transform to convert pixel coordinates to reference space
sfToRefT  = hSf.affine();                                  % get affine transfrom to convert scanfield coordinates to reference space

%% plot pixel coordinates
pixelResXY = hSf.pixelResolutionXY;                        % get scanfield pixel resolution
[xx,yy] = meshgrid(1:pixelResXY(1),1:pixelResXY(2));       % create mesh of pixel coordinates
[xx_ref,yy_ref] = most.idioms.xformMesh(xx,yy,hSf.pixToRefT);  % transform pixel mesh into reference coordinate space
% plot meshgrid in reference space
hFig = figure();
hAx = axes('Parent',hFig,'XLim',[0,1],'YLim',[0,1],'YDir','reverse','DataAspectRatio',[1,1,1]);
line('Parent',hAx,'XData',xx_ref(:),'YData',yy_ref(:),'Color',[0 0.5 1],'LineStyle','none','Marker','.');

%% plot scanfield outline
outlinePts = [0 0; 0 1; 1 1; 1 0; 0 0];
outlinePts_ref = most.idioms.xformPoints(outlinePts,sfToRefT);
line('Parent',hAx,'XData',outlinePts_ref (:,1),'YData',outlinePts_ref (:,2),'Color','red');

%% plot scanfield center
centerPt = [0.5,0.5];
centerPt_ref = most.idioms.xformPoints(centerPt,sfToRefT);
line('Parent',hAx,'XData',centerPt_ref(1),'YData',centerPt_ref(2),'Color','red','Marker','x','MarkerSize',10);
```

## RoiManager¶

All imaging RoiGroups are managed by the ScanImage® component hSI.hRoiManager. This component contains two RoiGroups:

• hSI.hRoiManager
• hSI.hRoiManager.roiGroupDefault (default, used for non-mRoi imaging)

• hSI.hRoiManager.roiGroupMroi (used for mRoi imaging)

hSI.hRoiManager.currentRoiGroup returns one of this roiGroups, depending if hSI.hRoiManager.mroiEnable is set to True or False

Attention

Do not change hSI.hRoiManager.roiGroupDefault directly. The scanfield of this RoiGroup is configured automatically by ScanImage® using the following properties in hSI.hRoiManager:

• hSI.hRoiManager.pixelsPerLine

• hSI.hRoiManager.linesPerFrame

• hSI.hRoiManager.scanZoomFactor

• hSI.hRoiManager.scanRotation

• hSI.hRoiManager.scanAngleMultiplierSlow

• hSI.hRoiManager.scanAngleMultiplierFast

• hSI.hRoiManager.scanAngleShiftSlow

• hSI.hRoiManager.scanAngleShiftFast

• hSI.hRoiManager.forceSquarePixelation

• hSI.hRoiManager.forceSquarePixels

Use hSI.hRoiManager.roiGroupDefault.rois(1).scanfields(1) to inspect the current scanning paramters