Python – How to Change the Color of a Particular Letter in Text Box Using PyQt4 and QGIS

pyqgispyqt4pythonqgis-2qt-designer

I need to highlight the particular letter in a text box using python.
I am using the below code but it changes the entire text color in text
box. Kindly suggest any other ideas.
I am using both QlineEdit and QTextEdit objects.

 if self.dlgAttribute.ui.txtPartDesc3.text()!="":
    partDescValue = self.dlgAttribute.ui.txtPartDesc3.text()
    if not partDescValue in self.englishArray:
        font.setPointSize(11)
        self.dlgAttribute.ui.txtPartDesc3.setFont(font)
        self.dlgAttribute.ui.txtPartDesc3.setStyleSheet(_fromUtf8("color: rgb(255, 162, 0);\n"
        "background-color: rgb(41, 91, 170);\n"
        "font: 750 10pt \"Arial\";"))
    else:
        font.setPointSize(11)
        self.dlgAttribute.ui.txtPartDesc3.setFont(font)
        self.dlgAttribute.ui.txtPartDesc3.setStyleSheet(_fromUtf8("color: rgb(0,0,0);\n"
        "background-color: rgb(255, 255, 255);\n"
        "font: 750 10pt \"Arial\";"))
else:
    font.setPointSize(11)
    self.dlgAttribute.ui.txtPartDesc3.setFont(font)
    self.dlgAttribute.ui.txtPartDesc3.setStyleSheet(_fromUtf8("color: rgb(0,0,0);\n"
    "background-color: rgb(255, 255, 255);\n"
    "font: 750 10pt \"Arial\";"))

Best Answer

You can use an HTML declaration to change the text color inside a text box.

An example is given on the following link: color in a qt text box

And here is an example of how to change only one letter: one letter color

Related Solutions

QGIS Python – How to Change Attributes

You are right, that you don't need to call commit if you work on the dataProvider directly. However, this will also commit every update immediately, leading to more I/O overhead (often decreased performance) and poor transaction handling. This is to say, the method works, but use it carefully. I have added another method below which is better suited in most cases.

The problem in the code is, that you are only setting the attribute on the feature in memory and don't tell the provider, that this feature changed. Instead, try the following code. It buffers all updates in the updateMap and then executes it in one go at the end, therefore allowing batch updates (useful e.g. on slow networks). Another possibility would be to issue updateAttributeValue directly in the loop.

from qgis.utils import iface
from PyQt4.QtCore import *

layers = iface.legendInterface().layers()

for layer in layers:
    name = layer.name()
    if name.endswith('x'):
        provider = layer.dataProvider()
        updateMap = {}
        fieldIdx = provider.fields().indexFromName( 'attr' )
        features = provider.getFeatures()
        for feature in features:
            updateMap[feature.id()] = { fieldIdx: 'a' }

        provider.changeAttributeValues( updateMap )

The generally recommended way:

with edit(layer):
    for feature in layer.getFeatures():
        feature['fieldName'] = newValue
        layer.updateFeature(feature)

http://qgis.org/api/2.2/classQgsVectorDataProvider.html#a99a5d01c33c1cadb7ae9209b68cd8743

[GIS] How to get the polygon vs. Polygon Intersection Coordinates using python

You need to consider the different possibilities for the geometry of polygon features intersection. Options could be a point, line or polygon. However, it is preferable to express the geometry directly as WKT because the code is more concise and it is easier to get a memory layer.

To try out my approach, first, I modified your code to:

import itertools

canvas = iface.mapCanvas()

aLayer = canvas.currentLayer()
selection = aLayer.selectedFeatures()
n=len(selection)
list = range(n)

for i,j in itertools.combinations(list, 2):
    geom = selection[i].geometry().intersection(selection[j].geometry())
    print geom.exportToWkt()

After running it with a two features shapefile, where the intersection is a polygon, I got:`

I used the QuickWKT plugin to put the polygon layer visible at the Map Canvas.

At the next situation, the features are adjacent and the intersection is a LineString; where the QuickWKT plugin was also used to visualize the line layer at the Map View.

I hope that it helps.

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