First draft of t8.py

demos/api/t8.py

+# This file reimplements gmsh/tutorial/t8.geo in Python.
+# It demonstrates post-processing, animations and using options.
+
+import gmsh
+
+model = gmsh.model
+factory = model.geo
+
+# adapted t1.py section {{{
+
+gmsh.initialize()
+gmsh.option.setNumber("General.Terminal", 1)
+
+lc = 1e-2
+factory.addPoint(0, 0, 0, lc, 1)
+factory.addPoint(.1, 0,  0, lc, 2)
+factory.addPoint(.1, .3, 0, lc, 3)
+factory.addPoint(0, .3, 0, lc, 4)
+
+factory.addLine(1, 2, 1)
+factory.addLine(3, 2, 2)
+factory.addLine(3, 4, 3)
+factory.addLine(4, 1, 4)
+
+factory.addCurveLoop([4, 1, -2, 3], 1)
+factory.addPlaneSurface([1], 1)
+
+model.addPhysicalGroup(0, [1, 2], 1)
+model.addPhysicalGroup(1, [1, 2], 2)
+model.addPhysicalGroup(2, [1], 6)
+
+model.setPhysicalName(2, 6, "My surface")
+
+model.geo.synchronize()
+# }}}
+
+# -- begin t8.py --
+
+# add post-processing views to work on
+gmsh.merge("view1.pos")
+gmsh.merge("view1.pos")
+gmsh.merge("view4.pos") # contains 2 views inside
+
+# set general options
+option = gmsh.option
+
+option.setNumber("General.Trackball", 0)
+
+option.setNumber("General.RotationX", 0)
+option.setNumber("General.RotationY", 0)
+option.setNumber("General.RotationZ", 0)
+
+white = (255, 255, 255)
+black = (0, 0, 0)
+
+# Color options are special
+# Setting a color option of "X.Y" actually sets the option "X.Color.Y"
+# Sets "General.Color.Background", etc.
+option.setColor("General.Background", white[0], white[1], white[2])
+
+# We can make our own shorter versions of repetitive methods
+set_color = lambda name, c: option.setColor(name, c[0], c[1], c[2])
+set_color("General.Foreground", black)
+set_color("General.Text", black)
+
+option.setNumber("General.Orthographic", 0)
+option.setNumber("General.Axes", 0); option.setNumber("General.SmallAxes", 0)
+
+# set options for each view
+
+# If we were to follow the geo example blindly, we would
+# read the number of views from the relevant option value
+#
+# Make sure to cast to int since getNumber returns a float
+# v0 = int(option.getNumber("PostProcessing.NbViews")) - 4
+# v1 = v0 + 1; v2 = v0 + 2; v3 = v0 + 3
+
+# A nicer way is to use gmsh.view.getTags()
+view_tags = [v0, v1, v2, v3] = gmsh.view.getTags()
+
+# View name format helper function -- Returns "View[X]." for an input of X
+view_fmt = lambda v: "View[" + str(v) + "]."
+
+# option setter
+def set_opt(name, val):
+    # if it's a string, call the string method
+    val_type = type(val)
+    if val_type == type("str"):
+        option.setString(name, val)
+    # otherwise call the number method
+    elif val_type == type(0.5) or val_type == type(1):
+        option.setNumber(name, val)
+    else:
+        print("error: bad input to set_opt: " + name + " = " + str(val))
+        print("error: set_opt is only meant for numbers and strings, aborting")
+        quit(1)
+
+# We'll use this helper function for our views
+set_view_opt = lambda v_num, name, val: set_opt(view_fmt(v_num) + name, val)
+
+# v0
+set_view_opt(v0, "IntervalsType", 2)
+set_view_opt(v0, "OffsetZ", 0.05)
+set_view_opt(v0, "RaiseZ", 0)
+set_view_opt(v0, "Light", 1)
+set_view_opt(v0, "ShowScale", 0)
+set_view_opt(v0, "SmoothNormals", 1)
+
+# v1
+set_view_opt(v1, "IntervalsType", 1)
+# can't set ColorTable in API yet
+# option.setColorTable(view_opt[v1] + "ColorTable", "{ Green, Blue }")
+set_view_opt(v1, "NbIso", 10)
+set_view_opt(v1, "ShowScale", 0)
+
+# v2
+set_view_opt(v2, "Name", "Test...")
+set_view_opt(v2, "Axes", 1)
+set_color(view_fmt(v2) + "Axes", black)
+set_view_opt(v2, "IntervalsType", 2)
+set_view_opt(v2, "Type", 2)
+set_view_opt(v2, "IntervalsType", 2)
+set_view_opt(v2, "AutoPosition", 0)
+set_view_opt(v2, "PositionX", 85)
+set_view_opt(v2, "PositionY", 50)
+set_view_opt(v2, "Width", 200)
+set_view_opt(v2, "Height", 130)
+
+# v3
+set_view_opt(v3, "Visible", 0)
+
+t = 0
+# step through time for each view
+for num in range(1, 4):
+
+    # update timesteps
+    for v in view_tags:
+        set_view_opt(v, "TimeStep", t)
+
+    # helper function to match the geo file's +=, -= operators for numbers
+    adjust_num_opt = lambda name, diff: set_opt(name, option.getNumber(name) + diff)
+
+    current_step = option.getNumber(view_fmt(v0) + "TimeStep")
+    max_step = option.getNumber(view_fmt(v0) + "NbTimeStep") - 1
+    if current_step < max_step:
+        t = t + 1
+    else:
+        t = 0
+
+    v0_max = option.getNumber(view_fmt(v0) + "Max")
+    adjust_num_opt(view_fmt(v0) + "RaiseZ", 0.01 / v0_max * t)
+
+    if num == 3:
+        set_opt("General.GraphicsWidth", option.getNumber("General.MenuWidth") + 640)
+        set_opt("General.GraphicsHeight", 480)
+
+    frames = 50
+    for num2 in range(frames):
+        adjust_num_opt("General.RotationX", 10)
+        set_opt("General.RotationY", option.getNumber("General.RotationX") / 3)
+        adjust_num_opt("General.RotationZ", 0.1)
+        gmsh.fltk.wait(0.01) # open the GUI, wait for 0.01s and resume execution
+        gmsh.graphics.draw()
+
+        # write out the graphics scene to an image file
+        # Gmsh will try to detect the file extension
+        if num == 3:
+            gmsh.write("t2-{:.2g}.gif".format(num2))
+            gmsh.write("t2-{:.2g}.ppm".format(num2))
+            gmsh.write("t2-{:.2g}.jpg".format(num2))
+
+    if num == 3:
+        pass
+        # Here we could make a system call to generate a movie. For example:
+        # import subprocess
+        # call_ffmpeg1 = "ffmpeg -hq -r 5 -b 800 -vcodec mpeg1video -i t8-%02d.jpg t8.mpg"
+        # call_ffmpeg2 = "ffmpeg -hq -r 5 -b 800 -i t8-%02d.jpg t8.asf"
+        # subprocess.call(call_ffmpeg1.split(' '))
+        # subprocess.call(call_ffmpeg2.split(' '))
+
+# show the GUI at the end
+gmsh.fltk.run()
+
+gmsh.finalize()