The rapid frame is designed to display a small section of the main image very rapidly, either in the main image (class RtdImageFrame ) or in a popup window (class RtdImagePopup ). The region being displayed in the rapid frame is marked by a black and a white dashed rectangle, which can be moved and resized interactively by dragging with the mouse. The rapid frame creates an instance of the RtdImage widget (for popup frames) or a second rtdimage canvas image item (for embedded frames), to display a section of the image. A notification facility is used to notify application specific code about changes in the position and size of the rapid frame, which normally will involve communication with the rtdServer , a daemon process that multiplexes real-time image events from CCD cameras to the display applications.
Here is an example showing how class RtdImage creates a rapid frame. This code is evaluated after the user draws a rectangle over the image. A callback procedure gets the coordinates and Id of the frame and creates it as follows:
RtdImageFrame $this.rapid \ -target_image $this \ -popup $popup \ -xoffset $xoffset \ -yoffset $yoffset \ -width $width \ -height $height \ -subsample $subsample \ -usexshm $usexshm \ -withdraw [expr !$popup] \ -region_id $region_id \ -verbose $verbose \ -command $rapid_frame_command
Since this frame is displayed as a canvas image item, there is no need to use pack here. For more details, see the man pages RtdImageFrame(n) and RtdImagePopup(n) in the Reference section.
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