Author Archives: dmitriano
Sending XRP with JavaScript
const read = require('read').read;
const send = require('./send');
async function asyncMain()
{
const amount = await read({
prompt: "Amount: "
});
const password = await read({
prompt: "Password: ",
silent: true,
replace: "*" //optional, will print out an asterisk for every typed character
});
// console.log("Amount: " + amount);
// console.log("Your password: " + password);
Viewing image metadata on Ubuntu 22.04
sudo apt install imagemagick
identify -verbose my-image.jpg
Make QML menu width fit the content
Found an implementation here and added two pixels:
import QtQuick
import QtQuick.Controls
import QtQuick.Layouts
Menu {
width: {
var result = 0;
var padding = 0;
for (var i = 0; i < count; ++i) {
var item = itemAt(i);
result = Math.max(item.contentItem.implicitWidth, result);
padding = Math.max(item.padding, padding);
}
// It looks like two pixels are missing to remove the ellipsis.
// My first idea was that it is leftInset + rightInset, but it does not work.
var missing = 2;
return result + padding * 2 + missing;
}
}
Converting MP4 to GIF with ffmpeg
I was able to convert MP4 to GIF with ffmpeg with the following commands on Ubuntu 22.04:
ffmpeg \
-i iphone884.mp4 \
-r 15 \
-vf "scale=512:-1,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" \
-ss 00:00:03 -to 00:00:06 \
iphone884.gif
ffmpeg \
-i iphone884.mp4 \
-r 15 \
-vf "scale=300:-1,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" \
iphone884.gif
Move assignment operator in C++
Implicitly-declared move assignment operator
If no user-defined move assignment operators are provided for a class type, and all of the following is true:
- there are no user-declared copy constructors;
- there are no user-declared move constructors;
- there are no user-declared copy assignment operators;
- there is no user-declared destructor,
(more…)
Examples of C++/Objective-C interop
From QT’s Purchasing:
//SKProductsRequestDelegate
-(void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response
{
NSArray<SKProduct *> *products = response.products;
SKProduct *product = [products count] == 1 ? [[products firstObject] retain] : nil;
if (product == nil) {
//Invalid product ID
NSString *invalidId = [response.invalidProductIdentifiers firstObject];
QMetaObject::invokeMethod(backend, "registerQueryFailure", Qt::AutoConnection, Q_ARG(QString, QString::fromNSString(invalidId)));
} else {
//Valid product query
//Create a IosInAppPurchaseProduct
IosInAppPurchaseProduct *validProduct = new IosInAppPurchaseProduct(product, backend->productTypeForProductId(QString::fromNSString([product productIdentifier])));
if (validProduct->thread() != backend->thread()) {
validProduct->moveToThread(backend->thread());
QMetaObject::invokeMethod(backend, "setParentToBackend", Qt::AutoConnection, Q_ARG(QObject*, validProduct));
}
QMetaObject::invokeMethod(backend, "registerProduct", Qt::AutoConnection, Q_ARG(IosInAppPurchaseProduct*, validProduct));
}
[request release];
}
Copy a file with CMake
Copy Podfile at the build stage:
message("Copy ${CMAKE_CURRENT_SOURCE_DIR}/Podfile -> ${CMAKE_BINARY_DIR}")
add_custom_target(copy_podfile
COMMAND ${CMAKE_COMMAND} -E copy_if_different
"${CMAKE_CURRENT_SOURCE_DIR}/Podfile"
"${CMAKE_BINARY_DIR}"
COMMENT "Copying Podfile"
)
add_dependencies(${PROJECT_NAME} copy_podfile)
Copy Podfile at the configuration stage:
execute_process(COMMAND ${CMAKE_COMMAND} -E copy_if_different
"${CMAKE_CURRENT_SOURCE_DIR}/Podfile"
"${CMAKE_BINARY_DIR}"
)
