Created
January 24, 2018 11:43
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This demonstrates how to use Mayavi/mlab to render a mesh object in a precise pixel location within a viewport of predetermined size.
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| import os | |
| os.environ["QT_API"] = "pyqt" | |
| import numpy as np | |
| import matplotlib.pyplot as plt | |
| from mayavi import mlab | |
| if __name__ == "__main__": | |
| # Create a test 100x100 RGB image: all black and a red border. This is to demonstrate how to align the viewport. | |
| img = np.zeros((100, 100, 3), dtype = np.uint8) | |
| img[[0, -1], :, 0] = 255 | |
| img[:, [0, -1], 0] = 255 | |
| # Create new Mayavi scene for rendering | |
| fig = mlab.figure(size = (img.shape[1], img.shape[0])) | |
| scene = fig.scene | |
| # Render the original image | |
| test = mlab.imshow(np.ones(img.shape[:2][::-1]), interpolate = False) | |
| # Add RGB color to the rendering | |
| colors = np.c_[img.reshape(-1, 3), 255 * np.ones(img.size//3, dtype = np.uint8)] | |
| test.actor.input.point_data.scalars = colors | |
| # Render a triangular mesh | |
| x = np.array([50, 40, 60]) - 1 | |
| y = np.array([20, 40, 40]) - 1 | |
| z = -np.ones(x.size) | |
| face = np.array([[0, 1, 2]]) | |
| tmesh = mlab.triangular_mesh(x - img.shape[1]/2, y - img.shape[0]/2, z, face, scalars = np.arange(x.size)) | |
| # Add texture to the triangular mesh | |
| texture = 255 * np.c_[np.eye(3, dtype = np.uint8), np.ones(x.size, dtype = np.uint8)] | |
| tmesh.module_manager.scalar_lut_manager.lut.table = texture | |
| # Remove the default Mayavi lighting | |
| tmesh.actor.property.lighting = False | |
| # Remove the toolbar in the figure window | |
| scene._tool_bar.setVisible(False) | |
| # Change the view of the scene to look at the x-y image plane | |
| mlab.view(180, 180, 'auto', 'auto') | |
| # Set a parallel projection for the scene camera | |
| scene.parallel_projection = True | |
| scene.camera.parallel_scale = (img.shape[0] - 1)/2 | |
| # Save the scene into a NumPy array | |
| rendering = mlab.screenshot() | |
| plt.figure() | |
| plt.imshow(rendering, interpolation = 'None') |
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