python - 绘制具有负高度的序列 Logo

Question

我正在使用 matplotlib.text 模块中的 TextPath 绘制文本。我部分使用了 this thread 中的代码，并绘制了负高度的图。它工作得很好，除了用负高度绘制的代码是垂直翻转的这一事实之外。但这对于“A”和“T”来说都不是问题。 “C”，尤其是“G”看起来很奇怪:

有没有办法真正垂直翻转文本？这是代码的一部分，尽管大部分是从 the thread mentioned above 复制的

import matplotlib as mpl
from matplotlib.text import TextPath
from matplotlib.patches import PathPatch
from matplotlib.font_manager import FontProperties
import matplotlib.pyplot as plt
import itertools
import operator
import numpy as np

fp = FontProperties(family="Arial", weight="bold") 
globscale = 1.35
LETTERS = { "T" : TextPath((-0.305, 0), "T", size=1, prop=fp),
            "G" : TextPath((-0.384, 0), "G", size=1, prop=fp),
            "A" : TextPath((-0.35, 0), "A", size=1, prop=fp),
            "C" : TextPath((-0.366, 0), "C", size=1, prop=fp) }
COLOR_SCHEME = {'G': 'gold', 
                'A': 'forestgreen', 
                'C': 'mediumblue', 
                'T': 'crimson'}

def letterAt(letter, x, y, yscale=1, ax=None):
    text = LETTERS[letter]

    t = mpl.transforms.Affine2D().scale(1*globscale, yscale*globscale) + \
        mpl.transforms.Affine2D().translate(x,y) + ax.transData
    p = PathPatch(text, lw=0, fc=COLOR_SCHEME[letter],  transform=t)
    if ax != None:
        ax.add_artist(p)
    return p

ALL_SCORES1 = [[('C', 0.02247014831444764),
          ('T', 0.057903843733384308),
          ('A', 0.10370837683591219),
          ('G', 0.24803586793255664)],
         [('T', 0.046608227674354567),
          ('G', 0.048827667087419063),
          ('A', 0.084338697696451109),
          ('C', 0.92994511407402669)],
         [('G', 0.0),
          ('T', 0.011098351287382456),
          ('A', 0.022196702574764911),
          ('C', 1.8164301607015951)],
         [('C', 0.020803153636453006),
          ('T', 0.078011826136698756),
          ('G', 0.11268374886412044),
          ('A', 0.65529933954826969)],
         [('T', 0.017393530660176126),
          ('A', 0.030438678655308221),
          ('G', 0.22611589858228964),
          ('C', 0.45078233627623127)],
         [('G', 0.022364103549245576),
          ('A', 0.043412671595594352),
          ('T', 0.097349627214363091),
          ('C', 0.1657574733649966)],
         [('C', 0.03264675899941203),
          ('T', 0.045203204768416654),
          ('G', 0.082872542075430544),
          ('A', 1.0949220710572034)],
         [('C', 0.0),
          ('T', 0.0076232429756614498),
          ('A', 0.011434864463492175),
          ('G', 1.8867526364762088)],
         [('C', 0.0018955903000026028),
          ('T', 0.0094779515000130137),
          ('A', 0.35637097640048931),
          ('G', 0.58005063180079641)],
         [('A', 0.01594690817903021),
          ('C', 0.017541598996933229),
          ('T', 0.2774762023151256),
          ('G', 0.48638069946042134)],
         [('A', 0.003770051401807444),
          ('C', 0.0075401028036148881),
          ('T', 0.011310154205422331),
          ('G', 1.8624053924928772)],
         [('C', 0.036479877757360731),
          ('A', 0.041691288865555121),
          ('T', 0.072959755514721461),
          ('G', 1.1517218549109602)],
         [('G', 0.011831087684038642),
          ('T', 0.068620308567424126),
          ('A', 0.10174735408273231),
          ('C', 1.0009100180696691)],
         [('C', 0.015871770937774379),
          ('T', 0.018757547471915176),
          ('A', 0.32176408355669878),
          ('G', 0.36505073156881074)],
         [('A', 0.022798100897300954),
          ('T', 0.024064662058262118),
          ('G', 0.24571286522646588),
          ('C', 0.34070495229855319)]]


fig, ax = plt.subplots(figsize=(10,3))

all_scores = ALL_SCORES1
x = 1
maxi = 2
for scores in all_scores:
    y = 0
    for base, score in scores:
        letterAt(base, x,y, -score, ax)
        y -= score
    x += 1
    maxi = max(maxi, y)

plt.xticks(range(1,x))
plt.xlim((0, x)) 
plt.ylim((-2, maxi)) 
plt.tight_layout()      
plt.show()

Answer 1

ImportanceOfBeingErnest 向我指出了解决方案:它既不是字母的翻转，也不是负高度的绘图，而只是改变 y 值的问题，绘图开始于:

fig, ax = plt.subplots(figsize=(10,3))
x = 1.0
maxi = 2
for scores in all_scores:
#sort the scores with "reverse=True" so most important letters are at the bottom
    scores=sorted(scores,key=operator.itemgetter(1),reverse=True)
#start plotting at the negative sum of all values below 0
    y = np.sum([-1*s[1] for s in scores])
    for base, score in scores:
        letterAt(base, x,y, score, ax)
        y += score
    x += 1
    maxi = max(maxi, y)


plt.xticks(np.arange(1,x))
plt.xlim((0, x)) 
plt.ylim((-2, maxi)) 
plt.tight_layout()      
plt.show()