如何从字符串/xml流在PyQT5中显示SVG图像? [英] How to show SVG image in PyQT5 from string/xml stream?
问题描述
在 Python3/QT5 应用程序中,我试图显示最初作为字符串构建的 SVG 图像.我需要操作这个 SVG 图像(例如改变它的颜色),所以我的字符串会随着时间的推移而改变.这是一个最小的工作示例:
In a Python3/QT5 application, I'm trying to show a SVG image built originally as a string. I need to manipulate this SVG image (e.g. change its color), so I have the string changing over time. Here is a minimal working example:
import sys
from PyQt5.QtWidgets import QApplication
from PyQt5.QtSvg import QSvgWidget
svg_str = """<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg width="300" height="300" viewBox="0 0 300 300" id="smile" version="1.1">
<path
style="fill:#ffaaaa"
d="M 150,0 A 150,150 0 0 0 0,150 150,150 0 0 0 150,300 150,150 0 0 0
300,150 150,150 0 0 0 150,0 Z M 72,65 A 21,29.5 0 0 1 93,94.33
21,29.5 0 0 1 72,124 21,29.5 0 0 1 51,94.33 21,29.5 0 0 1 72,65 Z
m 156,0 a 21,29.5 0 0 1 21,29.5 21,29.5 0 0 1 -21,29.5 21,29.5 0 0 1
-21,-29.5 21,29.5 0 0 1 21,-29.5 z m -158.75,89.5 161.5,0 c 0,44.67
-36.125,80.75 -80.75,80.75 -44.67,0 -80.75,-36.125 -80.75,-80.75 z"
/>
</svg>
"""
# ==========================================
with open('smile.svg', 'w') as f:
f.write(svg_str)
# ==========================================
app = QApplication(sys.argv)
svgWidget = QSvgWidget('smile.svg')
svgWidget.setGeometry(100,100,300,300)
svgWidget.show()
sys.exit(app.exec_())
我的问题是我找不到保存文件的方法,以便从字符串本身实例化 QSvgWidget
对象.我不想随意保存文件,也找不到将 xml
信息直接加载到 QSvgWidget
对象的方法...
My problem is that I couldn't find a way around the need to save the file in order to instantiate a QSvgWidget
object from the string itself. I don't want to save files indiscriminately and I couldn't find a way to load xml
information directly to a QSvgWidget
object...
我找到了一个最接近我的愿望的解决方案,它看起来像这样:
I found a solution closest to my desires, and it looks like this:
import sys
from PyQt5.QtWidgets import QApplication
from PyQt5.QtSvg import QSvgWidget, QSvgRenderer
from PyQt5.QtCore import QXmlStreamReader
from PyQt5.QtGui import QPainter
svg_str = """<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg width="300" height="300" viewBox="0 0 300 300" id="smile" version="1.1">
<path
style="fill:#ffaaaa"
d="M 150,0 A 150,150 0 0 0 0,150 150,150 0 0 0 150,300 150,150 0 0 0
300,150 150,150 0 0 0 150,0 Z M 72,65 A 21,29.5 0 0 1 93,94.33
21,29.5 0 0 1 72,124 21,29.5 0 0 1 51,94.33 21,29.5 0 0 1 72,65 Z
m 156,0 a 21,29.5 0 0 1 21,29.5 21,29.5 0 0 1 -21,29.5 21,29.5 0 0 1
-21,-29.5 21,29.5 0 0 1 21,-29.5 z m -158.75,89.5 161.5,0 c 0,44.67
-36.125,80.75 -80.75,80.75 -44.67,0 -80.75,-36.125 -80.75,-80.75 z"
/>
</svg>
"""
# ==========================================
class QSvgWidget_from_string(QSvgWidget):
def __init__(self, strSVG):
super().__init__()
self.strSVG = strSVG
def paintEvent(self, event):
qp = QPainter()
qp.begin(self)
svg_render = QSvgRenderer(QXmlStreamReader(self.strSVG))
qp.restore()
svg_render.render(qp)
qp.end()
# ==========================================
app = QApplication(sys.argv)
svgWidget = QSvgWidget_from_string(svg_str)
svgWidget.setGeometry(100,100,300,300)
svgWidget.show()
sys.exit(app.exec_())
但我并不满意,因为我需要扩展 QSvgWidget
类只是为了从 xml
字符串实例化它.我的问题是:有没有什么办法可以不用QPaint
和paintEvent
来做到这一点?
But I'm not satisfied because I need to expand QSvgWidget
class just to instantiate it from a xml
string. My question is: Is there any way of doing this without having to resort to QPaint
and paintEvent
?
推荐答案
您可以获得 QSvgWidget
使用的 QSvgRenderer
来渲染 SVG.它允许从文件、字节数组或流加载数据:
You can get the QSvgRenderer
used by the QSvgWidget
to render the SVG. It allows to load data from a file, byte array or a stream:
import sys
from PyQt5.QtWidgets import QApplication
from PyQt5.QtSvg import QSvgWidget, QSvgRenderer
svg_str = """<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg width="300" height="300" viewBox="0 0 300 300" id="smile" version="1.1">
<path
style="fill:#ffaaaa"
d="M 150,0 A 150,150 0 0 0 0,150 150,150 0 0 0 150,300 150,150 0 0 0
300,150 150,150 0 0 0 150,0 Z M 72,65 A 21,29.5 0 0 1 93,94.33
21,29.5 0 0 1 72,124 21,29.5 0 0 1 51,94.33 21,29.5 0 0 1 72,65 Z
m 156,0 a 21,29.5 0 0 1 21,29.5 21,29.5 0 0 1 -21,29.5 21,29.5 0 0 1
-21,-29.5 21,29.5 0 0 1 21,-29.5 z m -158.75,89.5 161.5,0 c 0,44.67
-36.125,80.75 -80.75,80.75 -44.67,0 -80.75,-36.125 -80.75,-80.75 z"
/>
</svg>
"""
svg_bytes = bytearray(svg_str, encoding='utf-8')
app = QApplication(sys.argv)
svgWidget = QSvgWidget()
svgWidget.renderer().load(svg_bytes)
svgWidget.setGeometry(100,100,300,300)
svgWidget.show()
sys.exit(app.exec_())
更多信息在这里:http://doc.qt.io/qt-5/qsvgrenderer.html
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