On 2022-04-07 22:04, Israel Brewster wrote:
On Apr 7, 2022, at 11:58 AM, Henry Skoglund <he...@tungware.se> wrote:
On 2022-04-07 20:28, Israel Brewster wrote:
Using Qt 5.15 and PySide2, I am working on a project that requires me to
produce a PDF output. My process so far is to create a QWidget containing the
content I want, render it to a QPicture (so it won’t be rasterized upon
“printing”), then create a PDF QPrinter and use the painter.drawPicture()
function to “print” the widget into a PDF.
This works well, giving me a high-quality vectorized PDF output, with one
exception: any item that is filled with a gradient. When printing to PDF, the
gradient always comes out as solid white. With some digging, I determined that
this is even the case when doing nothing but a simple painter.fillRect() with a
gradient.
Is there any “fix” for this? Thanks.
If it helps, here is some simple code that reproduces the issue:
from PySide2.QtWidgets import QApplication
from PySide2.QtGui import QPainter, QPageSize, QLinearGradient
from PySide2.QtPrintSupport import QPrinter
from PySide2.QtCore import QSize, QRect, Qt
app = QApplication()
gradient_rect = QRect(0, 0, 500, 25)
gradient = QLinearGradient(0, 0, 1, 0)
gradient.setColorAt(0, Qt.blue)
gradient.setColorAt(1, Qt.red)
page_size = QPageSize(QSize(500, 25), matchPolicy = QPageSize.ExactMatch)
printer = QPrinter()
printer.setOutputFormat(QPrinter.PdfFormat)
printer.setPageSize(page_size)
printer.setOutputFileName('/tmp/testPDFGradient.pdf')
painter = QPainter(printer)
painter.fillRect(gradient_rect, gradient)
painter.end()
Hi, try
...
gradient_rect = QRect(0, 0, 500, 25)
gradient = QLinearGradient(0, 0, 500, 25)
gradient.setColorAt(0, Qt.blue)
gradient.setColorAt(1, Qt.red)
...
(i.e. QLinearGradient's ctor expects coords)
No change. The 1 value was picked because that’s what displays correctly in
testing, but even with the suggested change I still get a solid white box.
Hmm, I just tested on Ubuntu 20.04, created an empty vanilla widget
program in Qt 5.15.2. added "printsupport" to the .pro file and changed
mainwindow.cpp to look like this:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "QtPrintSupport"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
auto gradient_rect = QRect(0,0,500,25);
auto gradient = QLinearGradient(0,0,500,25);
gradient.setColorAt(0,Qt::blue);
gradient.setColorAt(1,Qt::red);
QPrinter printer;
QPageSize ps(QSize(500,25),"GradientTest",QPageSize::ExactMatch);
printer.setOutputFormat(QPrinter::PdfFormat);
printer.setPageSize(ps);
printer.setOutputFileName("/home/henry/Downloads/testPDFGradient.pdf");
QPainter painter;
painter.begin(&printer);
painter.fillRect(gradient_rect,gradient);
painter.end();
}
MainWindow::~MainWindow()
{
delete ui;
}
screenshot here: https://tungware.se/GradientOnUbuntu.png
(also tested on Windows 10 MSVC2019 Qt 5.15.2 and works there as well)
Maybe pySide2 messes up something, you could try with some C++ :-)
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