Thanks for the help. Both ways worked exactly how I needed them to, but I also want to be able to set a sinusoidal and logarithmic transformation on the axes. Is this possible without using a matrix?
On Tuesday, July 12, 2022 at 10:17:47 PM UTC-7 [email protected] wrote: > In addition to what Patrick said; you can also call setRect on the image, > to place it where you want > > image.setRect(pg.Qt.QtCore.QRectF(x0, y0, width, height)) > > Keep in mind that x0 and y0 represent the top-left corner of the rectangle. > > On Tue, Jul 12, 2022 at 7:17 PM Patrick <[email protected]> wrote: > >> Hi Alan, >> >> The new, accepted way to do this is by applying a QTransform to the >> ImageItem. Something like this: >> >> # Axis labels or limits for the x and y pixels >> # If pixel values, they need to be uniform intervals >> x = np.array([-1024, 1024]) >> y = np.array([-1024, 1024]) >> >> # Scale in units per pixel >> x_scale = (x[-1] - x[0])/(x.shape[0]-1) if x.shape[0] > 1 else 1.0 >> y_scale = (y[-1] - y[0])/(y.shape[0]-1) if y.shape[0] > 1 else 1.0 >> >> # Create QTransform and apply to ImageItem >> # Adjust so values are centred on pixels >> tr = QtGui.QTransform() >> tr.translate(x[0] - x_scale/2, y[0] - y_scale/2) >> tr.scale(x_scale, y_scale) >> image.setTransform(tr) >> >> It's just calculating the translation and pixel scale required to map the >> pixel coordinates to the desired axis coordinates. >> >> Patrick >> >> >> >> >> >> On Wednesday, 13 July 2022 at 7:56:44 am UTC+9:30 Alan Wang wrote: >> >>> Hi all, >>> I'm making a graph that displays an image with an ImageItem and >>> GraphicsLayoutWidget, but I'd like to label the image with axes on a >>> different system of coordinates. When I create a graph, the axes go from 0 >>> to 4096 (the size of the image), but I'd like the axes to be labeled from >>> -1024 to 1024, essentially remapping the coordinates to a different scale. >>> Is there a way to do this? >>> >>> Thank you >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "pyqtgraph" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/pyqtgraph/85ab2e7c-5418-4946-9110-800983b05387n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/pyqtgraph/85ab2e7c-5418-4946-9110-800983b05387n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "pyqtgraph" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/pyqtgraph/e8bda188-65f0-4d42-9658-e2da78cdbd3en%40googlegroups.com.
