zulip/static/js/condense.js

246 lines
8.0 KiB
JavaScript

/*
This library implements two related, similar concepts:
- condensing, i.e. cutting off messages taller than about a half
screen so that they aren't distractingly tall (and offering a button
to uncondense them).
- Collapsing, i.e. taking a message and reducing its height to a
single line, with a button to see the content.
*/
const IntDict = require('./int_dict').IntDict;
const _message_content_height_cache = new IntDict();
function show_more_link(row) {
row.find(".message_condenser").hide();
row.find(".message_expander").show();
}
function show_condense_link(row) {
row.find(".message_expander").hide();
row.find(".message_condenser").show();
}
function condense_row(row) {
const content = row.find(".message_content");
content.addClass("condensed");
show_more_link(row);
}
function uncondense_row(row) {
const content = row.find(".message_content");
content.removeClass("condensed");
show_condense_link(row);
}
exports.uncollapse = function (row) {
// Uncollapse a message, restoring the condensed message [More] or
// [Condense] link if necessary.
const message = current_msg_list.get(rows.id(row));
message.collapsed = false;
message_flags.save_uncollapsed(message);
const process_row = function process_row(row) {
const content = row.find(".message_content");
content.removeClass("collapsed");
if (message.condensed === true) {
// This message was condensed by the user, so re-show the
// [More] link.
condense_row(row);
} else if (message.condensed === false) {
// This message was un-condensed by the user, so re-show the
// [Condense] link.
uncondense_row(row);
} else if (content.hasClass("could-be-condensed")) {
// By default, condense a long message.
condense_row(row);
} else {
// This was a short message, no more need for a [More] link.
row.find(".message_expander").hide();
}
};
// We also need to collapse this message in the home view
const home_row = home_msg_list.get_row(rows.id(row));
process_row(row);
process_row(home_row);
};
exports.collapse = function (row) {
// Collapse a message, hiding the condensed message [More] or
// [Condense] link if necessary.
const message = current_msg_list.get(rows.id(row));
message.collapsed = true;
if (message.locally_echoed) {
// Trying to collapse a locally echoed message is
// very rare, and in our current implementation the
// server response overwrites the flag, so we just
// punt for now.
return;
}
message_flags.save_collapsed(message);
const process_row = function process_row(row) {
row.find(".message_content").addClass("collapsed");
show_more_link(row);
};
// We also need to collapse this message in the home view
const home_row = home_msg_list.get_row(rows.id(row));
process_row(row);
process_row(home_row);
};
exports.toggle_collapse = function (message) {
if (message.is_me_message) {
// Disabled temporarily because /me messages don't have a
// styling for collapsing /me messages (they only recently
// added multi-line support). See also popovers.js.
return;
}
// This function implements a multi-way toggle, to try to do what
// the user wants for messages:
//
// * If the message is currently showing any [More] link, either
// because it was previously condensed or collapsed, fully display it.
// * If the message is fully visible, either because it's too short to
// condense or because it's already uncondensed, collapse it
const row = current_msg_list.get_row(message.id);
if (!row) {
return;
}
const content = row.find(".message_content");
const is_condensable = content.hasClass("could-be-condensed");
const is_condensed = content.hasClass("condensed");
if (message.collapsed) {
if (is_condensable) {
message.condensed = true;
content.addClass("condensed");
exports.show_message_expander(row);
row.find(".message_condenser").hide();
}
exports.uncollapse(row);
} else {
if (is_condensed) {
message.condensed = false;
content.removeClass("condensed");
exports.hide_message_expander(row);
row.find(".message_condenser").show();
} else {
exports.collapse(row);
}
}
};
exports.clear_message_content_height_cache = function () {
_message_content_height_cache.clear();
};
exports.un_cache_message_content_height = function (message_id) {
_message_content_height_cache.del(message_id);
};
function get_message_height(elem, message_id) {
if (_message_content_height_cache.has(message_id)) {
return _message_content_height_cache.get(message_id);
}
// shown to be ~2.5x faster than Node.getBoundingClientRect().
const height = elem.offsetHeight;
_message_content_height_cache.set(message_id, height);
return height;
}
exports.hide_message_expander = function (row) {
if (row.find(".could-be-condensed").length !== 0) {
row.find(".message_expander").hide();
}
};
exports.show_message_expander = function (row) {
if (row.find(".could-be-condensed").length !== 0) {
row.find(".message_expander").show();
}
};
exports.condense_and_collapse = function (elems) {
const height_cutoff = message_viewport.height() * 0.65;
_.each(elems, function (elem) {
const content = $(elem).find(".message_content");
const message = current_msg_list.get(rows.id($(elem)));
if (content !== undefined && message !== undefined) {
const message_height = get_message_height(elem, message.id);
const long_message = message_height > height_cutoff;
if (long_message) {
// All long messages are flagged as such.
content.addClass("could-be-condensed");
} else {
content.removeClass("could-be-condensed");
}
// If message.condensed is defined, then the user has manually
// specified whether this message should be expanded or condensed.
if (message.condensed === true) {
condense_row($(elem));
return;
} else if (message.condensed === false) {
uncondense_row($(elem));
return;
} else if (long_message) {
// By default, condense a long message.
condense_row($(elem));
} else {
content.removeClass('condensed');
$(elem).find(".message_expander").hide();
}
// Completely hide the message and replace it with a [More]
// link if the user has collapsed it.
if (message.collapsed) {
content.addClass("collapsed");
$(elem).find(".message_expander").show();
}
}
});
};
exports.initialize = function () {
$("#home").on("click", ".message_expander", function () {
// Expanding a message can mean either uncollapsing or
// uncondensing it.
const row = $(this).closest(".message_row");
const message = current_msg_list.get(rows.id(row));
const content = row.find(".message_content");
if (message.collapsed) {
// Uncollapse.
exports.uncollapse(row);
} else if (content.hasClass("condensed")) {
// Uncondense (show the full long message).
message.condensed = false;
content.removeClass("condensed");
$(this).hide();
row.find(".message_condenser").show();
}
});
$("#home").on("click", ".message_condenser", function () {
const row = $(this).closest(".message_row");
current_msg_list.get(rows.id(row)).condensed = true;
condense_row(row);
});
};
window.condense = exports;