当光标悬停在 matplotlib 绘图上时是否可以绑定滚轮进行放大/缩小？
这应该有效。当您滚动时，它会将图表重新置于指针位置的中心。
import matplotlib.pyplot as plt
def zoom_factory(ax,base_scale = 2.):
def zoom_fun(event):
# get the current x and y limits
cur_xlim = ax.get_xlim()
cur_ylim = ax.get_ylim()
cur_xrange = (cur_xlim[1] - cur_xlim[0])*.5
cur_yrange = (cur_ylim[1] - cur_ylim[0])*.5
xdata = event.xdata # get event x location
ydata = event.ydata # get event y location
if event.button == 'up':
# deal with zoom in
scale_factor = 1/base_scale
elif event.button == 'down':
# deal with zoom out
scale_factor = base_scale
else:
# deal with something that should never happen
scale_factor = 1
print event.button
# set new limits
ax.set_xlim([xdata - cur_xrange*scale_factor,
xdata + cur_xrange*scale_factor])
ax.set_ylim([ydata - cur_yrange*scale_factor,
ydata + cur_yrange*scale_factor])
plt.draw() # force re-draw
fig = ax.get_figure() # get the figure of interest
# attach the call back
fig.canvas.mpl_connect('scroll_event',zoom_fun)
#return the function
return zoom_fun
假设你有一个轴对象
axax.plot(range(10))
scale = 1.5
f = zoom_factory(ax,base_scale = scale)
可选参数
base_scale请务必保留一份
ff写完这个答案后，我认为这实际上非常有用，并将其放入要点
谢谢大家，这些例子非常有帮助。我必须进行一些更改才能使用散点图，并且通过左键拖动添加了平移。希望有人会发现这很有用。
from matplotlib.pyplot import figure, show
import numpy
class ZoomPan:
def __init__(self):
self.press = None
self.cur_xlim = None
self.cur_ylim = None
self.x0 = None
self.y0 = None
self.x1 = None
self.y1 = None
self.xpress = None
self.ypress = None
def zoom_factory(self, ax, base_scale = 2.):
def zoom(event):
cur_xlim = ax.get_xlim()
cur_ylim = ax.get_ylim()
xdata = event.xdata # get event x location
ydata = event.ydata # get event y location
if event.button == 'down':
# deal with zoom in
scale_factor = 1 / base_scale
elif event.button == 'up':
# deal with zoom out
scale_factor = base_scale
else:
# deal with something that should never happen
scale_factor = 1
print event.button
new_width = (cur_xlim[1] - cur_xlim[0]) * scale_factor
new_height = (cur_ylim[1] - cur_ylim[0]) * scale_factor
relx = (cur_xlim[1] - xdata)/(cur_xlim[1] - cur_xlim[0])
rely = (cur_ylim[1] - ydata)/(cur_ylim[1] - cur_ylim[0])
ax.set_xlim([xdata - new_width * (1-relx), xdata + new_width * (relx)])
ax.set_ylim([ydata - new_height * (1-rely), ydata + new_height * (rely)])
ax.figure.canvas.draw()
fig = ax.get_figure() # get the figure of interest
fig.canvas.mpl_connect('scroll_event', zoom)
return zoom
def pan_factory(self, ax):
def onPress(event):
if event.inaxes != ax: return
self.cur_xlim = ax.get_xlim()
self.cur_ylim = ax.get_ylim()
self.press = self.x0, self.y0, event.xdata, event.ydata
self.x0, self.y0, self.xpress, self.ypress = self.press
def onRelease(event):
self.press = None
ax.figure.canvas.draw()
def onMotion(event):
if self.press is None: return
if event.inaxes != ax: return
dx = event.xdata - self.xpress
dy = event.ydata - self.ypress
self.cur_xlim -= dx
self.cur_ylim -= dy
ax.set_xlim(self.cur_xlim)
ax.set_ylim(self.cur_ylim)
ax.figure.canvas.draw()
fig = ax.get_figure() # get the figure of interest
# attach the call back
fig.canvas.mpl_connect('button_press_event',onPress)
fig.canvas.mpl_connect('button_release_event',onRelease)
fig.canvas.mpl_connect('motion_notify_event',onMotion)
#return the function
return onMotion
fig = figure()
ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
ax.set_title('Click to zoom')
x,y,s,c = numpy.random.rand(4,200)
s *= 200
ax.scatter(x,y,s,c)
scale = 1.1
zp = ZoomPan()
figZoom = zp.zoom_factory(ax, base_scale = scale)
figPan = zp.pan_factory(ax)
show()
def zoom(self, event, factor):
curr_xlim = self.ax.get_xlim()
curr_ylim = self.ax.get_ylim()
new_width = (curr_xlim[1]-curr_ylim[0])*factor
new_height= (curr_xlim[1]-curr_ylim[0])*factor
relx = (curr_xlim[1]-event.xdata)/(curr_xlim[1]-curr_xlim[0])
rely = (curr_ylim[1]-event.ydata)/(curr_ylim[1]-curr_ylim[0])
self.ax.set_xlim([event.xdata-new_width*(1-relx),
event.xdata+new_width*(relx)])
self.ax.set_ylim([event.ydata-new_width*(1-rely),
event.ydata+new_width*(rely)])
self.draw()
这个稍微改变的代码的目的是跟踪光标相对于新缩放中心的位置。这样，如果您在中心以外的点放大和缩小图片，您仍会保留在同一点上。
非常感谢。这效果很好。然而，对于比例不再是线性的图（例如对数图），这种情况就会失效。我为此编写了一个新版本。我希望它对某人有帮助。
基本上，我放大标准化为 [0,1] 的轴坐标。因此，如果我将 x 放大两倍，我现在希望处于 [.25, .75] 范围内。 我还添加了一项功能，仅在 x 轴的正上方或正下方时才放大 x，而在 y 轴的正左侧或右侧时仅放大 y。如果不需要，只需设置 Zoomx=True 和 Zoomy = True 并忽略 if 语句。
此参考对于那些想要了解 matplotlib 如何在不同坐标系之间转换的人非常有用：http://matplotlib.org/users/transforms_tutorial.html
此函数位于包含指向轴的指针 (self.ax) 的对象内。
def zoom(self,event):
'''This function zooms the image upon scrolling the mouse wheel.
Scrolling it in the plot zooms the plot. Scrolling above or below the
plot scrolls the x axis. Scrolling to the left or the right of the plot
scrolls the y axis. Where it is ambiguous nothing happens.
NOTE: If expanding figure to subplots, you will need to add an extra
check to make sure you are not in any other plot. It is not clear how to
go about this.
Since we also want this to work in loglog plot, we work in axes
coordinates and use the proper scaling transform to convert to data
limits.'''
x = event.x
y = event.y
#convert pixels to axes
tranP2A = self.ax.transAxes.inverted().transform
#convert axes to data limits
tranA2D= self.ax.transLimits.inverted().transform
#convert the scale (for log plots)
tranSclA2D = self.ax.transScale.inverted().transform
if event.button == 'down':
# deal with zoom in
scale_factor = self.zoom_scale
elif event.button == 'up':
# deal with zoom out
scale_factor = 1 / self.zoom_scale
else:
# deal with something that should never happen
scale_factor = 1
#get my axes position to know where I am with respect to them
xa,ya = tranP2A((x,y))
zoomx = False
zoomy = False
if(ya < 0):
if(xa >= 0 and xa <= 1):
zoomx = True
zoomy = False
elif(ya <= 1):
if(xa <0):
zoomx = False
zoomy = True
elif(xa <= 1):
zoomx = True
zoomy = True
else:
zoomx = False
zoomy = True
else:
if(xa >=0 and xa <= 1):
zoomx = True
zoomy = False
new_alimx = (0,1)
new_alimy = (0,1)
if(zoomx):
new_alimx = (np.array([1,1]) + np.array([-1,1])*scale_factor)*.5
if(zoomy):
new_alimy = (np.array([1,1]) + np.array([-1,1])*scale_factor)*.5
#now convert axes to data
new_xlim0,new_ylim0 = tranSclA2D(tranA2D((new_alimx[0],new_alimy[0])))
new_xlim1,new_ylim1 = tranSclA2D(tranA2D((new_alimx[1],new_alimy[1])))
#and set limits
self.ax.set_xlim([new_xlim0,new_xlim1])
self.ax.set_ylim([new_ylim0,new_ylim1])
self.redraw()
我真的很喜欢图中的“仅x”或“仅y”模式。您可以绑定 x 和 y 键，以便仅在一个方向上进行缩放。请注意，如果单击输入框或其他内容，您可能还必须将焦点放回到画布上 -
canvas.mpl_connect('button_press_event', lambda event:canvas._tkcanvas.focus_set())其余修改后的代码如下：
from matplotlib.pyplot import figure, show
import numpy
class ZoomPan:
def __init__(self):
self.press = None
self.cur_xlim = None
self.cur_ylim = None
self.x0 = None
self.y0 = None
self.x1 = None
self.y1 = None
self.xpress = None
self.ypress = None
self.xzoom = True
self.yzoom = True
self.cidBP = None
self.cidBR = None
self.cidBM = None
self.cidKeyP = None
self.cidKeyR = None
self.cidScroll = None
def zoom_factory(self, ax, base_scale = 2.):
def zoom(event):
cur_xlim = ax.get_xlim()
cur_ylim = ax.get_ylim()
xdata = event.xdata # get event x location
ydata = event.ydata # get event y location
if(xdata is None):
return()
if(ydata is None):
return()
if event.button == 'down':
# deal with zoom in
scale_factor = 1 / base_scale
elif event.button == 'up':
# deal with zoom out
scale_factor = base_scale
else:
# deal with something that should never happen
scale_factor = 1
print(event.button)
new_width = (cur_xlim[1] - cur_xlim[0]) * scale_factor
new_height = (cur_ylim[1] - cur_ylim[0]) * scale_factor
relx = (cur_xlim[1] - xdata)/(cur_xlim[1] - cur_xlim[0])
rely = (cur_ylim[1] - ydata)/(cur_ylim[1] - cur_ylim[0])
if(self.xzoom):
ax.set_xlim([xdata - new_width * (1-relx), xdata + new_width * (relx)])
if(self.yzoom):
ax.set_ylim([ydata - new_height * (1-rely), ydata + new_height * (rely)])
ax.figure.canvas.draw()
ax.figure.canvas.flush_events()
def onKeyPress(event):
if event.key == 'x':
self.xzoom = True
self.yzoom = False
if event.key == 'y':
self.xzoom = False
self.yzoom = True
def onKeyRelease(event):
self.xzoom = True
self.yzoom = True
fig = ax.get_figure() # get the figure of interest
self.cidScroll = fig.canvas.mpl_connect('scroll_event', zoom)
self.cidKeyP = fig.canvas.mpl_connect('key_press_event',onKeyPress)
self.cidKeyR = fig.canvas.mpl_connect('key_release_event',onKeyRelease)
return zoom
def pan_factory(self, ax):
def onPress(event):
if event.inaxes != ax: return
self.cur_xlim = ax.get_xlim()
self.cur_ylim = ax.get_ylim()
self.press = self.x0, self.y0, event.xdata, event.ydata
self.x0, self.y0, self.xpress, self.ypress = self.press
def onRelease(event):
self.press = None
ax.figure.canvas.draw()
def onMotion(event):
if self.press is None: return
if event.inaxes != ax: return
dx = event.xdata - self.xpress
dy = event.ydata - self.ypress
self.cur_xlim -= dx
self.cur_ylim -= dy
ax.set_xlim(self.cur_xlim)
ax.set_ylim(self.cur_ylim)
ax.figure.canvas.draw()
ax.figure.canvas.flush_events()
fig = ax.get_figure() # get the figure of interest
self.cidBP = fig.canvas.mpl_connect('button_press_event',onPress)
self.cidBR = fig.canvas.mpl_connect('button_release_event',onRelease)
self.cidBM = fig.canvas.mpl_connect('motion_notify_event',onMotion)
# attach the call back
#return the function
return onMotion
使用
ax.set_xlim()ax.set_ylim()ax.drag_pan()def mousewheel_move( event):
ax=event.inaxes
ax._pan_start = types.SimpleNamespace(
lim=ax.viewLim.frozen(),
trans=ax.transData.frozen(),
trans_inverse=ax.transData.inverted().frozen(),
bbox=ax.bbox.frozen(),
x=event.x,
y=event.y)
if event.button == 'up':
ax.drag_pan(3, event.key, event.x+10, event.y+10)
else: #event.button == 'down':
ax.drag_pan(3, event.key, event.x-10, event.y-10)
fig=ax.get_figure()
fig.canvas.draw_idle()
然后将你的人物与：
fig.canvas.mpl_connect('scroll_event',mousewheel_move)
使用 TkAgg 后端和 python 3.6 使用 matplotlib 3.0.2 进行测试
这是对上面代码稍作修改的建议 - 它使保持缩放居中更易于管理。
cur_xrange = (cur_xlim[1] - cur_xlim[0])*.5
cur_yrange = (cur_ylim[1] - cur_ylim[0])*.5
xmouse = event.xdata # get event x location
ymouse = event.ydata # get event y location
cur_xcentre = (cur_xlim[1] + cur_xlim[0])*.5
cur_ycentre = (cur_ylim[1] + cur_ylim[0])*.5
xdata = cur_xcentre+ 0.25*(xmouse-cur_xcentre)
ydata = cur_ycentre+ 0.25*(ymouse-cur_ycentre)
据我所知，还有另一种方法。一次偶然的机会，我遇到了 Axis.zoom 方法。我不知道这是否更快或总体上是一个好方法，但它有效并且代码肯定更少：
def __init(self):
...
self.cid_zoom = self.canvas.mpl_connect('scroll_event', self.zoom)
def zoom(self, event):
if event.inaxes == self.ax:
scale_factor = np.power(self.zoom_factor, -event.step)*event.step
self.ax.get_xaxis().zoom(scale_factor)
self.ax.get_yaxis().zoom(scale_factor)
self.ax.invert_yaxis()
self.canvas.draw_idle()
如果您绘制图像，由于某种原因，您必须再次反转 y 轴。
您也可以通过这种方式实现平移，但效果并不是很好。我不知道为什么：
def __init(self):
...
self.cid_motion = self.canvas.mpl_connect(
'motion_notify_event', self.pan_move
)
self.cid_button = self.canvas.mpl_connect(
'button_press_event', self.pan_press
)
def pan_press(self, event):
if event.inaxes == self.ax:
self.x_press = event.xdata
self.y_press = event.ydata
def pan_move(self, event):
if event.button == 1 and event.inaxes == self.ax:
xdata = event.xdata
ydata = event.ydata
dx = (xdata - self.x_press)/np.diff(self.ax.get_xlim())
dy = (ydata - self.y_press)/np.diff(self.ax.get_ylim())
self.ax.get_xaxis().pan(-dx)
self.ax.get_yaxis().pan(-dy)
self.ax.drag_pan(event.button, event.key, dx, dy)
self.canvas.draw()
使 tacaswell 的答案“顺利”
def zoom_factory(ax, base_scale=2.):
prex = 0
prey = 0
prexdata = 0
preydata = 0
def zoom_fun(event):
nonlocal prex, prey, prexdata, preydata
curx = event.x
cury = event.y
# if not changed mouse position(or changed so little)
# remain the pre scale center
if abs(curx - prex) < 10 and abs(cury - prey) < 10:
# remain same
xdata = prexdata
ydata = preydata
# if changed mouse position ,also change the cur scale center
else:
# change
xdata = event.xdata # get event x location
ydata = event.ydata # get event y location
# update previous location data
prex = event.x
prey = event.y
prexdata = xdata
preydata = ydata
# get the current x and y limits
cur_xlim = ax.get_xlim()
cur_ylim = ax.get_ylim()
cur_xrange = (cur_xlim[1] - cur_xlim[0]) * .5
cur_yrange = (cur_ylim[1] - cur_ylim[0]) * .5
# log.debug((xdata, ydata))
if event.button == 'up':
# deal with zoom in
scale_factor = 1 / base_scale
elif event.button == 'down':
# deal with zoom out
scale_factor = base_scale
else:
# deal with something that should never happen
scale_factor = 1
print(event.button)
# set new limits
ax.set_xlim([
xdata - cur_xrange * scale_factor,
xdata + cur_xrange * scale_factor
])
ax.set_ylim([
ydata - cur_yrange * scale_factor,
ydata + cur_yrange * scale_factor
])
plt.draw() # force re-draw
fig = ax.get_figure() # get the figure of interest
# attach the call back
fig.canvas.mpl_connect('scroll_event', zoom_fun)
# return the function
return zoom_fun