gristlabs_grist-core/app/client/components/Printing.ts

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import {CustomView} from 'app/client/components/CustomView';
import {DataRowModel} from 'app/client/models/DataRowModel';
import DataTableModel from 'app/client/models/DataTableModel';
import {ViewSectionRec} from 'app/client/models/DocModel';
import {prefersDarkMode, prefersDarkModeObs} from 'app/client/ui2018/cssVars';
import {dom} from 'grainjs';
type RowId = number|'new';
/**
* Print the specified viewSection (aka page widget). We use the existing view instance rather
* than render a new one, since it may have state local to this instance view, such as current
* filters.
*
* Views get a chance to render things specially for printing (which is needed when they use
* scrolly for normal rendering).
*
* To let an existing view print across multiple pages, we can't have it nested in a flexbox or a
* div with 'height: 100%'. We achieve it by forcing all parents of our view to have a simple
* layout. This is potentially fragile.
*/
export async function printViewSection(layout: any, viewSection: ViewSectionRec) {
const viewInstance = viewSection.viewInstance.peek();
const sectionElem = viewInstance?.viewPane?.closest('.viewsection_content');
if (!sectionElem) {
throw new Error("No page widget to print");
}
if (viewInstance instanceof CustomView) {
try {
await viewInstance.triggerPrint();
return;
} catch (e) {
// tslint:disable-next-line:no-console
console.warn(`Failed to trigger print in CustomView: ${e}`);
// continue on to trying to print from outside, which should work OK for a single page.
}
}
function prepareToPrint(onOff: boolean) {
// window.print() is a blocking call, which means our listener for the
// `prefers-color-scheme: dark` media feature will not receive any updates for the
// duration that the print dialog is shown. This proves problematic since an event is
// sent just before the blocking call containing a value of false, regardless of the
// user agent's color scheme preference. It's not clear why this happens, but the result
// is Grist temporarily reverting to the light theme until the print dialog is dismissed.
// As a workaround, we'll temporarily pause our listener, and unpause after the print dialog
// is dismissed.
prefersDarkModeObs().pause();
// Hide all layout boxes that do NOT contain the section to be printed.
layout?.forEachBox((box: any) => {
if (!box.dom.contains(sectionElem)) {
box.dom.classList.toggle('print-hide', onOff);
}
});
// Mark the section to be printed.
sectionElem.classList.toggle('print-widget', onOff);
// Let the view instance update its rendering, e.g. to render all rows when scrolly is in use.
viewInstance?.prepareToPrint(onOff);
// If .print-all-rows element is present (created for scrolly-based views), use it as the
// start element for the loop below, to ensure it's rendered flexbox-free.
const keyElem = sectionElem.querySelector('.print-all-rows') || sectionElem;
// Go through all parents of the element to be printed. For @media print, we override their
// layout in a heavy-handed way, forcing them all to be non-flexbox and sized to content,
// since our normal flexbox-based layout is sized to screen and would not print multiple pages.
let elem = keyElem.parentElement;
while (elem) {
elem.classList.toggle('print-parent', onOff);
elem = elem.parentElement;
}
}
const sub1 = dom.onElem(window, 'beforeprint', () => prepareToPrint(true));
const sub2 = dom.onElem(window, 'afterprint', (window as any).afterPrintCallback = () => {
sub1.dispose();
sub2.dispose();
// To debug printing, set window.debugPrinting=1 in the console, then print a section, dismiss
// the print dialog, switch to "@media print" emulation, and you can explore the styles. You'd
// need to call window.finishPrinting() or reload the page to do it again.
if ((window as any).debugPrinting) {
(window as any).finishPrinting = () => prepareToPrint(false);
} else {
prepareToPrint(false);
}
delete (window as any).afterPrintCallback;
prefersDarkModeObs().pause(false);
// This may have changed while window.print() was blocking.
prefersDarkModeObs().set(prefersDarkMode());
});
// Running print on a timeout makes it possible to test printing using selenium, and doesn't
// seem to affect normal printing.
setTimeout(() => window.print(), 0);
}
/**
* Produces a div with all requested rows using the same renderRow() function as used with scrolly
* for dynamically rendered views. This is used for printing, so these rows do not subscribe to
* data.
*
* To avoid creating a lot of subscriptions when rendering rows this way, we render one DOM row at
* a time, copy the produced HTML, and dispose the produced DOM.
*/
export function renderAllRows(
tableModel: DataTableModel, rowIds: RowId[], renderRow: (r: DataRowModel) => Element,
) {
const rowModel = tableModel.createFloatingRowModel(null) as DataRowModel;
const html: string[] = [];
rowIds.forEach((rowId, index) => {
if (rowId !== 'new') {
rowModel._index(index);
rowModel.assign(rowId);
const elem = renderRow(rowModel);
html.push(`<div class="print-row">${elem.outerHTML}</div>`);
dom.domDispose(elem);
}
});
rowModel.dispose();
const result = dom('div.print-all-rows');
result.innerHTML = html.join("\n");
return result;
}