On 2022-04-07 23:08, Israel Brewster wrote:
On Apr 7, 2022, at 12:59 PM, Henry Skoglund <he...@tungware.se> wrote:
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++ :-)
Interesting…must be a MacOS thing then. I just tried your C++ code
with the exact same results - plain white rectangle. So the only
difference I can see now is that you tested on Windows and Linux,
while I am testing on MacOS.
Wonderfull. Now I apparently need different code depending on which OS
I am running on (assuming I can get this to work on MacOS at all)...
---
I fired up my Mac, tested my code above on Qt 6.2.4 and verified I got
the same "A whiter shade of pale" as you.
Then I tested by copying a working .pdf from Ubuntu into Monterey, it
also displayed as totally white (when double-clicked or when viewed in
Safari).
But when I copied the .PDF generated in Monterey into Ubuntu, guess
what: it displayed correctly.
But it gets better! Guess what happens if you choose to view the PDF on
Monterey with either Chrome or Firefox (instead of Safari), then the
blue-red gradient lights up, yes even on the Mac :-)
Interesting, right?
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