VCS Text Objects¶
- Introduction
- Positioning Text
- Text Table Section
- Text Orientation Section
- Mathematical Expressions and Symbols
- Example: Bringing it all together
Introduction¶
VCS let you plot text objects on a plot.
# Styling for notebook
from __future__ import print_function
from IPython.core.display import HTML
HTML("""
<style>
.output_png {
display: table-cell;
text-align: center;
vertical-align: middle;
}
</style>
""")
import vcs
canvas=vcs.init(geometry=(800,600),bg=True)
txt = vcs.createtext()
txt.list()
As you can see VCS text pbjects are composed of two part the texttable and the textorientation
Text Table controls the font, color, actual text (string), and location options Text Orientation control the text font, size and alignements
Controling Placements of Text Objects¶
Please refer to the VCS Principles for details on viewport and worldcoordinates.
Essentially the viewport describe the area on the canvas where to draw, and the world coordinates are used within this area. Both are initialized at [0,1,0,1]
txt.string = 'Hello VCS User' # Or list of strings
txt.x = .5 # Or list of coordinates
txt.y = .5
canvas.plot(txt)
print(vcs.listelements("font"))
You can also access font by their number, you can get a font name based on its number or vice-versa get a font number based on its name
print("The 'Times' font number is:",vcs.getfontnumber("Times"))
print("The name of number 5 is:", vcs.getfont(5))
Default font¶
If you wish to change vcs default font (will affect every object using font 1) you can use setdefaultfont
canvas.clear()
t = canvas.createtext()
t.string = "Default as default font"
t.x = .3
t.halign = "center"
t.y = .5
canvas.plot(t)
vcs.setdefaultfont("DejaVuSans-Bold")
t = canvas.createtext()
t.string = "DejaVuSans-Bold as default font"
t.x = .7
t.halign = "center"
t.y = .5
canvas.plot(t)
Example:
# rest to default font: AvantGarde
vcs.setdefaultfont("AvantGarde")
fonts = vcs.listelements("font")
N = len(fonts)
grid = 5. # 5x5 grid
delta = 1./6.
canvas.clear()
for i, font in enumerate(fonts):
print("I,f:",i,font)
txt.font = font
txt.string = font
yindx = i % grid
xindx = int(i/grid)
txt.x = delta + xindx*delta
txt.y = delta + yindx*delta
dsp = canvas.plot(txt)
# Resets
txt.x = [.5]
txt.y = [.5]
txt.string = "A VCS Text Object"
dsp
Adding fonts¶
You can add TrueType fonts to vcs by using the canvas.addfont function
canvas.clear()
vcs.addfont("FFF_Tusj.ttf", name="Myfont")
txt.font = "Myfont"
canvas.plot(txt)
Color¶
You can control the font color via the color attribute, you can send a string representing the color name, an index in the text object colormap.
You can change the colormap via the colormap attribute
canvas.clear()
txt.font = "default"
txt.color = "Red"
canvas.plot(txt)
txt.x[0] += .2
txt.color = 5
canvas.plot(txt)
txt.colormap = "AMIP" # Changing the colormap chjange the color of index 5
txt.x[0] -= .4
canvas.plot(txt)
Projection¶
IF your worldcoordinates are representing lat/lon, you can use the projection attribute to apply a projection (and its settings) to your text location.
canvas.clear()
import cdms2, os
f=cdms2.open(os.path.join(vcs.sample_data,"clt.nc"))
bot = canvas.gettemplate("bot_of2")
top = canvas.gettemplate("top_of2")
gm = canvas.createisoline()
gm.datawc_x1 = -180
gm.datawc_x2 = 180
gm.datawc_y1 = -90
gm.datawc_y2 = 90
canvas.plot(f("clt", slice(0,1)),gm,top)
proj = "polar"
gm.projection = proj
canvas.plot(f("clt",slice(0,1),longitude=(-180,181)),gm,bot)
txt = canvas.createtext()
txt.string = "Non proj"
txt.worldcoordinate = [-180,180,-90,90]
txt.x = -30
txt.y = 80
txt.color="blue"
txt.height = 15
txt.halign = "center"
txt.viewport = top.data.x1, top.data.x2, top.data.y1, top.data.y2
canvas.plot(txt)
txt.projection = proj
txt.color = "red"
txt.string = "PROJECTED"
txt.viewport = bot.data.x1, bot.data.x2, bot.data.y1, bot.data.y2
canvas.plot(txt)# canvas.plot(txt)
Ordering in the plot¶
you can control the layer on which the object will be drawn via the priority attribute. Higher priority object are drawn on top of lower priority ones.
txt.priority = 0 # Turn off
txt.priority = 2 # move to a layer on top of "default" layer (1)
canvas.clear()
txt = vcs.createtext()
txt.string = "Example of BIG Text"
txt.x = .5
txt.y = .5
txt.height = 30
canvas.plot(txt)
Angle¶
You can control the clockwise rotation of a text object as shown bellow:
canvas.clear()
txt.angle = 45
txt.height =20.
txt.string = "A Rotated Text"
canvas.plot(txt)
canvas.clear()
line = vcs.createline()
line.x = [.5,.5]
line.y = [0.,1.]
line.type ="dot"
line.color=["grey"]
center = vcs.createtext()
center.x = .5
center.y = .5
center.string = "Centered Text"
center.halign = "center"
right = vcs.createtext()
right.x = .5
right.y = .25
right.string = "Right Aligned Text"
right.halign = "right"
left = vcs.createtext()
left.x = .5
left.y = .75
left.string = "Left Aligned Text"
left.halign = "left"
canvas.plot(center)
canvas.plot(right)
canvas.plot(left)
canvas.plot(line)
Vertical Alignement¶
You can control the vertical alignement via the valign attribute, possible values are: ('top', 'cap', 'half', 'base', 'bottom') or (0, 1, 2, 3, 4)
Note that cap is the same as top at the moment
canvas.clear()
line = vcs.createline()
line.y = [.5,.5]
line.x = [0.,1.]
line.type ="dot"
line.color=["grey"]
half = vcs.createtext()
half.height = 20
half.halign = "center"
half.x = .5
half.y = .5
half.string = "Half Aligned Text"
half.valign = "Half"
bottom = vcs.createtext()
bottom.halign='center'
bottom.height=20
bottom.x = .25
bottom.y = .5
bottom.string = "Bottom Aligned Text"
bottom.valign = "bottom"
top = vcs.createtext()
top.halign='center'
top.height=20
top.x = .75
top.y = .5
top.string = "Top Aligned Text"
top.valign = "top"
cap = vcs.createtext()
cap.x = .75
cap.y = .75
cap.string = "Cap Aligned Text"
cap.valign = "cap"
canvas.plot(half)
canvas.plot(bottom)
canvas.plot(top)
canvas.plot(line)
canvas.clear()
import cdms2, os
f=cdms2.open(os.path.join(vcs.sample_data,"clt.nc"))
# Continental U.S.A. region
lat1 = 15.
lat2 = 70.
lon1 = -140.
lon2 = -60.
proj = "lambert"
# Read data in
clt = f("clt",time=slice(0,1),latitude=(lat1,lat2),longitude=(lon1,lon2),squeeze=1)
# Isofill method
gm = vcs.createisofill()
gm.datawc_x1 = lon1
gm.datawc_x2 = lon2
gm.datawc_y1 = lat1
gm.datawc_y2 = lat2
gm.projection = proj
# Template (not modified)
templ = vcs.createtemplate()
# Text object
txt = vcs.createtext()
txt.string = ["Washington D.C.", "New York", "Los Angeles"]
txt.halign = "center"
txt.valign = "half"
txt.color = "red"
txt.font = "Myfont"
txt.height = 15
txt.priority = 2
txt.angle = -5
txt.y = [38.9072, 40.7128, 34.0522]
txt.x = [-77.0369, -74.0060, -118.2437]
txt.worldcoordinate = [lon1, lon2, lat1, lat2]
txt.viewport = [templ.data.x1, templ.data.x2, templ.data.y1, templ.data.y2]
txt.projection = proj
# Plot text first to show priority
canvas.plot(txt)
# Now data plotted "bellow" text
canvas.plot(clt,gm)
