I have difficulties around changing TextView Constraints. I don't find any example how to get Integer values of Constraints. I need them for initial values before code execution.
Initial constraints are created in IB, but I need to get value for variable in code to change them with multitouch gestures. I have TextView filled with text for reading. I already arranged that with pinch I can change Font size of text with min and max values. Now I want to change TextView width with rotate gesture.
Here is part of code for pinch gesture to change font size.
//Change font size
func pinchRecognized(pinch: UIPinchGestureRecognizer) {
//get pinch value (less than 1) fingers towards each other, (more than 1) fingers apart
let pScale = pinch.scale
//get current font size
let pFont = Int((ReadTextView.font?.pointSize)!)
if pScale > 1 {
if pFont <= maxFontSize {
ReadTextView.increaseFontSize()
}
}
else if pScale < 1 {
if pFont >= minFontSize {
ReadTextView.decreaseFontSize()
}
}
else {
// do nothing
}
defaults.set(pFont, forKey: "FontSize")
}
I like now to change width of TextView with rotate gesture. To start shrink I need initial values of left (leading) and right (trailing) margins.
Related
I have trouble getting TreeView in GTK3 to wrap text correctly.
I set it up to wrap in this way:
Gtk::TreeViewColumn* pColumn = mTreeView.get_column(2);
static_cast<Gtk::CellRendererText *>(pColumn->get_first_cell())
->property_wrap_mode().set_value(Pango::WRAP_WORD_CHAR);
static_cast<Gtk::CellRendererText *>(pColumn->get_first_cell())
->property_wrap_width().set_value(200);
This works, text is wrapped, but when I resize the window and make it bigger, there is a lot of ugly white-space above and below cell with long text. It seems, that GTK reserves height for cell based on wrap width. Which makes no sense to me.
I tried to get around with setting needed in signal_check_resize with calculating needed width like this:
Gtk::TreeViewColumn* pColumn = mTreeView.get_column(2);
auto width = this->get_allocated_width()
- mTreeView.get_column(0)->get_width()
- mTreeView.get_column(1)->get_width();
static_cast<Gtk::CellRendererText *>(pColumn->get_first_cell())
->property_wrap_width().set_value(width-100);
this->forceRecreateModel = true; //Needed to work
But this lets me only make window bigger. It cannot be shrinked, after it was resized.
The question is, how this is properly done?
I am using gtk3.20.3-1 and gtkmm3.20.1-1 on Arch linux.
EDIT: fixed typo in the title...
In the end I found how to do it.
In the setup of the window (for me constructor of the window derived class) it was necessary to set column to be AUTOSIZE in order to allow shrinking of the width.
//Last Column setup
{
mTreeView.append_column("Translation", mColumns.mEnglish);
Gtk::TreeViewColumn* pColumn = mTreeView.get_column(2);
pColumn->set_sizing(Gtk::TreeViewColumnSizing::TREE_VIEW_COLUMN_AUTOSIZE);
static_cast<Gtk::CellRendererText *>(pColumn->get_first_cell())
->property_wrap_mode().set_value(Pango::WRAP_WORD_CHAR);
}
Also there is needed to set correct wrap width on every resize. Without this, height of the row was as big as it would be necessary for currently set wrap_width with no regard on current width (resulting in big padding on the top, when stretched more and prohibiting to make window smaller).
This code was also in the constructor.
this->signal_check_resize().connect([this]()
{
//calculate remaining size
Gtk::TreeViewColumn* pColumn = mTreeView.get_column(2);
auto width = this->get_allocated_width()
- mTreeView.get_column(0)->get_width()
- mTreeView.get_column(1)->get_width()-30;
//minimum reasonable size for column
if(width < 150)
width = 150;
static_cast<Gtk::CellRendererText *>(pColumn->get_first_cell())
->property_wrap_width().set_value(width);
//debounce
static auto oldsize = 0;
{
oldsize = width;
//trigger redraw of mTreeView (by clearing and refilling Model,
//it is done in 100ms pulse)
this->mRedrawNeeded = true;
}
});
And maybe it is worth noting, that I have mTreeView encapsulated in Gtk::ScrolledWindow. So this is a chunk which comes before column setup. :)
//in class is: Gtk::ScrolledWindow mScrollForResults;
//scrolling area
mGrid.attach(mScrollForResults, 0,2,10,1);
mScrollForResults.set_hexpand();
mScrollForResults.set_policy(Gtk::PolicyType::POLICY_AUTOMATIC,
Gtk::PolicyType::POLICY_ALWAYS);
mScrollForResults.set_margin_top(10);
mScrollForResults.set_min_content_width(400);
mScrollForResults.set_min_content_height(200);
mScrollForResults.add(mTreeView);
//results treeView
mRefListStore = Gtk::ListStore::create(mColumns);
mTreeView.set_model(mRefListStore);
mTreeView.set_hexpand();
mTreeView.set_vexpand();
I am attempting to lower the font size of a TLabel if its text is to large to fit in the confines of the label. I didn't see any properties I could set on the label to achieve this, so I have tried writing my own method. My method works by using TCanvas.TextWidth to measure the width of the text in a label, and shrink the font until the width of the text fits within the width of the label.
void __fastcall ShrinkFontToFitLabel( TCanvas * Canvas, TLabel * Label )
{
float NewFontSize = Label->Font->Size;
Canvas->Font->Family = Label->Font->Family;
Canvas->Font->Size = NewFontSize;
while( Canvas->TextWidth( Label->Text ) > Label->Width && NewFontSize > MinimumFontSize )
{
NewFontSize -= FontSizeDecrement;
Canvas->Font->Size = NewFontSize;
}
Label->Font->Size = NewFontSize;
}
This works some of the time, however other times it does not shrink the font near enough. It seems as if the value I get from calling Canvas->TextWidth is a lot of times, much smaller than the number of pixels wide the label actually needs to be in order to fit the text.
Am I using Canvas->TextWidth incorrectly? Is there a better way to calculate the width of a string, or to re-size the font of a TLabel so its text fits within its demensions?
Edit:
In this case, I am passing in to my function, the TCanvas that my label is sitting in. I have tried using that TCanvas as well as Label->Canvas. Both give me the same number for text width, and both are short of the actual value in pixels needed to display the whole string.
The following code is taken from code that works in an FMX application, modified slightly to remove arrays that are being iterated through and declaring a variable locally to the function. It is being run in a TForm method. Canvas here is the Form's Canvas. You can see that I'm using "- 35" at one point - this might be because the numbers weren't quite right.
double InitialFontSize = 30;
Canvas->Font->Size = InitialFontSize;
StoryHeadlineLabel->Font->Size = InitialFontSize;
bool fits = false;
do
{
double widthA = Canvas->TextWidth (StoryHeadlineLabel->Text);
if (widthA > StoryHeadlineLabel->Width - 35)
{
StoryHeadlineLabel->Font->Size --;
Canvas->Font->Size --;
}
else
fits = true;
if (StoryHeadlineLabel->Font->Size < 6)
fits = true;
} while (!fits);
I try to scroll a scroll
view to a certain position
by setPosition(x).
For a short moment the scroller
moves scroll area to the correct
position, but bounces immediately
back.
How to do this right?
With Famo.us 0.3, it seems to be working like this.
Let's say that:
My scrollview's display area is 250 pixels in height
The contents of my scrollview are total of 1000 pixels in height
I want to scroll to the very bottom of the scrollview
The code:
// Scrollview area height 250 pixels
var myScrollviewArea = 250;
// My scrollview contents' total height 1000 pixels
var myScrollviewContents = 1000;
// Contents - Area = total pixels to scroll
var scrollpx = myScrollviewContents - myScrollviewArea;
// Setting scrollview to use the first element as offset origin
myScrollview.getOffset(1);
// Setting scroll position with setOffset()
myScrollview.setOffset(scrollpx);
UPDATE
The above code seems to work very randomly, because the offset index changes.
Here's some updated code, still a bit twitchy but works:
function _scrollToBottom() {
if(myScrollviewSurfaces) {
// Pixels to scroll
var scrollpx = 0;
// Current first visible element
var index = myScrollview.getCurrentIndex();
// Offset from the top of the index
var offset = myScrollview.getOffset();
// Calculating the distance from index to bottom
for(var i = index; i < myScrollviewSurfaces.length; i++) {
scrollpx = scrollpx + myScrollviewSurfaces[index].getSize(true)[1];
}
if(offset > 0) {
scrollpx = scrollpx - offset;
}
scrollpx = scrollpx - myScrollview.getSize(true)[1];
if(scrollpx > 0) {
myScrollview.setVelocity(1);
myScrollview.setPosition(scrollpx);
}
}
}
I got it now.
The Scrollview adds a spring to the particle. When moving only the particle, the spring moves it back to it anchor.
Setting the the spring-anchor to same position fixes the problem.
scrollview.setPosition(x)
scrollview.spring.setAnchor(x)
Set the option on the scrollview. It is the size of the area (in pixels) that Scrollview will display content in.
Scrollview that spans 400px:
scrollview.setOptions({
clipSize: 400,
});
Scrollview that spans your entire context:
scrollview.setOptions({
clipSize: mainContext.getSize()[1],
});
I am using CSCrollView window for our Application in which i have table drawn in View.
I have derived the CMYclass from CSCrollView, But whenevr i am scrolling the window up and down whatever i have drwan is getting erased. How i can acheive it this... i need to perform same actvity like a Word Pad is doing with images and Text. I want to keep scroll the View Vertically. Till the page ends.
Here is the code snippet:-
void CMyView::OnInitialUpdate()
{
CSize sizeTotal;
// TODO: calculate the total size of this view
sizeTotal.cx = 450;
sizeTotal.cy = 700;
SetScrollSizes(MM_TEXT, sizeTotal);
}
void CMyView::OnDraw(CDC* pDC)
{
for(int i = 1;i<50;++i)
{
AddRow(pDC);
TopPos = Height+TopPos;// ![Outpu Window Image][1]
nCountRow++;
}
}
it is only drawing 18 rows, but when iam scrolling down above drawn content is no more and also there is nothing coming up in scrolled area.
Is there anything more need to add?
Thanking for help
Regards,
Mukesh
Long time I have used CScrollView. Here is my hint: Try mapping modes other than MM_TEXT. Also look up other functions in CScrollView. I suggest to draw simple stuff first than some complicated rows.
I have QGraphicsTextItem objects on a QGraphicsScene. The user can scale the QGraphicsTextItem objects by dragging the corners. (I am using a custom "transformation editor" to do this.) The user can also change the size of the QGraphicsTextItem by changing the font size from a property panel. What I would like to do is unify these so that when the user scales the object by dragging the corner with the mouse, behind the scenes it actually is calculating "What size font is necessary to make the resulting object fit the target size and keep the scale factor at 1.0?"
What I am doing now is letting the object scale as normal using QGraphicsItem::mouseMoveEvent and then triggering a FinalizeMapScale method in QGraphicsItem::mouseReleaseEvent once the mouse scale is complete. This method should then change the font to the appropriate size and set the scale back to 1.0.
I have a solution that appears to be working, but I'm not crazy about it. I'm relatively new to both Qt and C++, so would appreciate any comments or corrections.
Is there a better way to architect this whole thing?
Are there Qt methods that already do this?
Is my method on the right track but has some Qt or C++ errors?
Feel free to comment on my answer below on submit your own preferred solution. Thanks!
[EDIT] As requested in comment, here is the basics of the scaling code. We actually went a different direction with this, so this code (and the code below) is no longer being used. This code is in the mouseMoveEvent method, having previously set a "scaling_" flag to true in mousePressEvent if the mouse was clicked in the bottom-right "hot spot". Note that this code is in a decorator QGraphicsItem that holds a pointer to the target it is scaling. This abstraction was necessary for our project, but is probably overkill for most uses.
void TransformDecorator::mouseMoveEvent(QGraphicsSceneMouseEvent *event) {
...
if (scaling_) {
QGraphicsItem *target_item = target_->AsQGraphicsItem();
target_item->setTransformOriginPoint(0.0, 0.0);
QPointF origin_scene = mapToScene(target_item->transformOriginPoint());
QPointF scale_position_scene = mapToScene(event->pos());
qreal unscaled_width = target_item->boundingRect().width();
qreal scale_x = (scale_position_scene.x() - origin_scene.x()) / unscaled_width;
if (scale_x * unscaled_width < kMinimumSize) {
scale_x = kMinimumSize / unscaled_width;
}
target_item->setScale(scale_x);
} else {
QGraphicsObject::mouseMoveEvent(event);
}
}
Please no holy wars about the loop-with-exit construct. We're comfortable with it.
void MapTextElement::FinalizeMapScale() {
// scene_document_width is the width of the text document as it appears in
// the scene after scaling. After we are finished with this method, we want
// the document to be as close as possible to this width with a scale of 1.0.
qreal scene_document_width = document()->size().width() * scale();
QString text = toPlainText();
// Once the difference between scene_document_width and the calculated width
// is below this value, we accept the new font size.
const qreal acceptable_delta = 1.0;
// If the difference between scene_document_width and the calculated width is
// more than this value, we guess at the new font size by calculating a new
// scale factor. Once it is beneath this value, we creep up (or down) by tiny
// increments. Without this, we would sometimes incur long "back and forth"
// loops when using the scale factor.
const qreal creep_delta = 8.0;
const qreal creep_increment = 0.1;
QScopedPointer<QTextDocument> test_document(document()->clone());
QFont new_font = this->font();
qreal delta = 0.0;
// To prevent infinite loops, we store the font size values that we try.
// Because of the unpredictable (at least to me) relationship between font
// point size and rendering size, this was the only way I could get it to
// work reliably.
QList<qreal> attempted_font_sizes;
while (true) {
test_document->setDefaultFont(new_font);
delta = scene_document_width - test_document->size().width();
if (std::abs(delta) <= acceptable_delta ||
attempted_font_sizes.contains(new_font.pointSizeF())) {
break;
}
attempted_font_sizes.append(new_font.pointSizeF());
qreal new_font_size = 0.0;
if (std::abs(delta) <= creep_delta) {
new_font_size = delta > 0.0 ? new_font.pointSizeF() + creep_increment
: new_font.pointSizeF() - creep_increment;
} else {
new_font_size = new_font.pointSizeF()
* scene_document_width
/ test_document->size().width();
}
new_font.setPointSizeF(new_font_size);
}
this->setFont(new_font);
this->setScale(1.0);
}
Another way to look at the problem is: Qt has scaled the font, what is the effective font size (as it appears to the user, not the font size set in the text item) that I need to display to the user as their choice of new font size? This is just an alternative, you still need a calculation similar to yours.
I have a similar problem. I have a text item that I want to be unit size (one pixel size) like my other unit graphic items (and then the user can scale them.) What font (setPointSize) needs to be set? (Also what setTextWidth and what setDocumentMargin?) The advantage of this design is that you don't need to treat the scaling of text items different than the scaling of any other shape of graphics item. (But I don't have it working yet.)
Also, a user interface issue: if the user changes the font size, does the item change size? Or does it stay the same size and the text wrap differently, leaving more or less blank space at the end of the text? When the user appends new text, does the font size change so all the text fits in the size of the shape, or does the shape size grow to accommodate more text? In other words, is it more like a flowchart app (where the shape size is fixed and the font shrinks), or like a word processor app (where the font size is constant and the shape (number of pages) grows?