I just cannot get the png image to display, I check that it loads correctly which is does but nothing is displayed on my blank canvases. The third one is meant to display an image. Can someone please have a quick look? Thanks.
QImage * QI = new QImage;
bool Check = QI->load("test.png");
QGraphicsPixmapItem * QII = new QGraphicsPixmapItem(QPixmap::fromImage(*QI));
QRect ImagePanelArea1(0, MenuBarHeight,
ScreenWidth / 3, (ScreenHeight / 2) - MenuBarHeight);
QRect ImagePanelArea2(ScreenWidth / 3, MenuBarHeight,
ScreenWidth / 3, (ScreenHeight / 2) - MenuBarHeight);
QRect ImagePanelArea3((ScreenWidth / 3) * 2, MenuBarHeight,
ScreenWidth / 3, (ScreenHeight / 2) - MenuBarHeight);
QGraphicsScene * QGS1 = new QGraphicsScene(ImagePanelArea1, this);
QGraphicsScene * QGS2 = new QGraphicsScene(ImagePanelArea2, this);
QGraphicsScene * QGS3 = new QGraphicsScene(ImagePanelArea3, this);
QGS3->addItem(QII);
QGraphicsView * QGV1 = new QGraphicsView(QGS1, this);
QGV1->setGeometry(ImagePanelArea1);
QGV1->show();
QGraphicsView * QGV2 = new QGraphicsView(QGS2, this);
QGV2->setGeometry(ImagePanelArea2);
QGV2->show();
QGraphicsView * QGV3 = new QGraphicsView(QGS3, this);
QGV3->setGeometry(ImagePanelArea3); QGV3->show();
Are you sure that you item is not outside of your scene QGS3?
QII is at the position (0;0). The QRect of your scene is defined between the point ((ScreenWidth / 3) * 2, MenuBarHeight) and the point (ScreenWidth / 3, (ScreenHeight / 2) - MenuBarHeight).
So, if your image is less larger than (ScreenWidth / 3) * 2, your item will be not visible.
Related
label=new QLabel(this);
label->setGeometry(this->width()/2,this->height()/2,label->width(),label->height());
QPixmap myPixmapForNow;
myPixmapForNow.load("C://Users//abc//Documents//QpixMap//hub_needle.png");
label->setMinimumSize(QSize(myPixmapForNow.width(),myPixmapForNow.width()));
label->setAlignment(Qt::AlignCenter);
QPixmap rotated(label->width(),label->width());
QPainter p(&rotated);
p.setRenderHint(QPainter::Antialiasing);
p.setRenderHint(QPainter::SmoothPixmapTransform);
p.setRenderHint(QPainter::HighQualityAntialiasing);
p.translate(myPixmapForNow.size().width() / 2,
(myPixmapForNow.size().height() / 2));
qDebug()<<"before rotation width:"<<rotated.size().width()<<"height:"<<rotated.size().width();
p.rotate(arg1);
p.translate(-myPixmapForNow.size().width() / 2,
-(myPixmapForNow.size().height() / 2));
qDebug()<<"after rotation height:"<<-rotated.size().width()<<"height:"<<-rotated.size().height();[![enter image description here][1]][1]
p.drawPixmap(QRect(0,0,myPixmapForNow.width(),myPixmapForNow.height()), myPixmapForNow);
p.end();
label->setPixmap(rotated);
After rotation
before rotation
I must admit the OP could have explained the issue a bit more in detail. Unfortunately, OP didn't react on comments.
However, out of curiosity, I tried to puzzle this out in a little demo. (I really like to write little Qt demos, especially with image manipulation and cat pictures.)
My first assumption was that OP has struggled with the order of transformations.
While translations are commutative (changing order doesn't change result), this is not the case for rotations (and other transformations).
However, after having wrapped OPs code into a MCVE, I convinced myself that the order of transformations matched my expectation – a rotation about the center of image.
So, I focused on the title
how to avoid pixmap cutting issues when we using qpainter while rotation
The reason for the “cutting issue” is simple:
To paint a rotated image (rectangle), the output may require a greater range of pixels then the original.
There are two possibilities to fix this:
enlarge the QPixmap for output
scale the result to match the original size of QPixmap.
So, this leaves the task to determine the output size of the rotated image beforehand, to either make the output QPixmap respectively larger or to add the respective scaling.
The bounding rectangle of a rotated rectangle can be calculated with trigonometric functions (sin, cos, etc.) I decided instead (for an IMHO more naïve way) to let Qt do the work for me.
To achieve this, the transformation has to be calculated before creating the QPixmap and QPainter. Hence, the prior
qPainter.translate(cx, cy);
qPainter.rotate(ra);
qPainter.translate(-cx, -cy);
is replaced by:
QTransform xform;
xform.translate(cx, cy);
xform.rotate(ra);
xform.translate(-cx, -cy);
which can be later applied as is:
qPainter.setTransform(xform);
I used the fact that all four corners of the rotated rectangle will touch the bounding rectangle. So, the bounding rectangle can be calculated by applying min() and max() to the x and y components of the rotated image corners:
const QPoint ptTL = xform * QPoint(0, 0);
const QPoint ptTR = xform * QPoint(w - 1, 0);
const QPoint ptBL = xform * QPoint(0, h - 1);
const QPoint ptBR = xform * QPoint(w - 1, h - 1);
QRect qRectBB(
QPoint(
min(ptTL.x(), ptTR.x(), ptBL.x(), ptBR.x()),
min(ptTL.y(), ptTR.y(), ptBL.y(), ptBR.y())),
QPoint(
max(ptTL.x(), ptTR.x(), ptBL.x(), ptBR.x()),
max(ptTL.y(), ptTR.y(), ptBL.y(), ptBR.y())));
Afterwards, the output may be adjusted using the origin and size of qRectBB.
The whole demo application testQPainterRotateCenter.cc:
#include <algorithm>
// Qt header:
#include <QtWidgets>
int min(int x0, int x1, int x2, int x3)
{
return std::min(std::min(x0, x1), std::min(x2, x3));
}
int max(int x0, int x1, int x2, int x3)
{
return std::max(std::max(x0, x1), std::max(x2, x3));
}
QPixmap rotate(
const QPixmap &qPixMapOrig, int cx, int cy, int ra,
bool fitIn, bool keepSize)
{
int w = qPixMapOrig.width(), h = qPixMapOrig.height();
QTransform xform;
xform.translate(cx, cy);
xform.rotate(ra);
xform.translate(-cx, -cy);
if (fitIn) {
// find bounding rect
const QPoint ptTL = xform * QPoint(0, 0);
const QPoint ptTR = xform * QPoint(w - 1, 0);
const QPoint ptBL = xform * QPoint(0, h - 1);
const QPoint ptBR = xform * QPoint(w - 1, h - 1);
QRect qRectBB(
QPoint(
min(ptTL.x(), ptTR.x(), ptBL.x(), ptBR.x()),
min(ptTL.y(), ptTR.y(), ptBL.y(), ptBR.y())),
QPoint(
max(ptTL.x(), ptTR.x(), ptBL.x(), ptBR.x()),
max(ptTL.y(), ptTR.y(), ptBL.y(), ptBR.y())));
qDebug() << "Bounding box:" << qRectBB;
// translate top left corner to (0, 0)
xform *= QTransform().translate(-qRectBB.left(), -qRectBB.top());
if (keepSize) {
// center align scaled image
xform *= w > h
? QTransform().translate((w - h) / 2, 0)
: QTransform().translate(0, (h - w) / 2);
// add scaling to transform
const qreal sx = qreal(w) / qRectBB.width();
const qreal sy = qreal(h) / qRectBB.height();
const qreal s = std::min(sx, sy);
xform *= QTransform().scale(s, s);
} else {
// adjust w and h
w = qRectBB.width(); h = qRectBB.height();
}
}
QPixmap qPixMap(w, h);
qPixMap.fill(Qt::gray);
{ QPainter qPainter(&qPixMap);
qPainter.setRenderHint(QPainter::Antialiasing);
qPainter.setRenderHint(QPainter::SmoothPixmapTransform);
qPainter.setRenderHint(QPainter::HighQualityAntialiasing);
qPainter.setTransform(xform);
qPainter.drawPixmap(0, 0, qPixMapOrig.width(), qPixMapOrig.height(), qPixMapOrig);
} // end of scope -> finalize QPainter
return qPixMap;
}
// main application
int main(int argc, char **argv)
{
qDebug() << "Qt Version:" << QT_VERSION_STR;
QApplication app(argc, argv);
// setup data
const QString file = QString::fromUtf8("cats.jpg");
QPixmap qPixMapOrig;
qPixMapOrig.load(file);
int cx = qPixMapOrig.width() / 2, cy = qPixMapOrig.height() / 2;
int ra = 0;
// setup GUI
QWidget qWin;
qWin.setWindowTitle(
file % QString(" (")
% QString::number(qPixMapOrig.width())
% " x " % QString::number(qPixMapOrig.height())
% ") - testQPainterRotateCenter");
QVBoxLayout qVBox;
QHBoxLayout qHBox1;
QLabel qLblCX(QString::fromUtf8("center x:"));
qHBox1.addWidget(&qLblCX);
QLineEdit qEditCX;
qEditCX.setText(QString::number(cx));
qHBox1.addWidget(&qEditCX, 1);
QLabel qLblCY(QString::fromUtf8("center y:"));
qHBox1.addWidget(&qLblCY);
QLineEdit qEditCY;
qEditCY.setText(QString::number(cy));
qHBox1.addWidget(&qEditCY, 1);
QLabel qLblRA(QString::fromUtf8("rotation angle:"));
qHBox1.addWidget(&qLblRA);
QSpinBox qEditRA;
qEditRA.setValue(ra);
qHBox1.addWidget(&qEditRA, 1);
qVBox.addLayout(&qHBox1);
QHBoxLayout qHBox2;
QCheckBox qTglFitIn(QString::fromUtf8("Zoom to Fit"));
qTglFitIn.setChecked(false);
qHBox2.addWidget(&qTglFitIn);
QCheckBox qTglKeepSize(QString::fromUtf8("Keep Size"));
qTglKeepSize.setChecked(false);
qHBox2.addWidget(&qTglKeepSize);
qVBox.addLayout(&qHBox2);
QLabel qLblImg;
qLblImg.setPixmap(qPixMapOrig);
qLblImg.setAlignment(Qt::AlignCenter);
qVBox.addWidget(&qLblImg, 1);
qWin.setLayout(&qVBox);
qWin.show();
// helper to update pixmap
auto update = [&]() {
cx = qEditCX.text().toInt();
cy = qEditCY.text().toInt();
ra = qEditRA.value();
const bool fitIn = qTglFitIn.isChecked();
const bool keepSize = qTglKeepSize.isChecked();
QPixmap qPixMap = rotate(qPixMapOrig, cx, cy, ra, fitIn, keepSize);
qLblImg.setPixmap(qPixMap);
};
// install signal handlers
QObject::connect(&qEditCX, &QLineEdit::textChanged,
[&](const QString&) { update(); });
QObject::connect(&qEditCY, &QLineEdit::textChanged,
[&](const QString&) { update(); });
QObject::connect(&qEditRA, QOverload<int>::of(&QSpinBox::valueChanged),
[&](int) { update(); });
QObject::connect(&qTglFitIn, &QCheckBox::toggled,
[&](bool) { update(); });
QObject::connect(&qTglKeepSize, &QCheckBox::toggled,
[&](bool) { update(); });
// runtime loop
return app.exec();
}
The Qt project file testQPainterRotateCenter.pro:
SOURCES = testQPainterRotateCenter.cc
QT += widgets
Output:
The rotated image without zoom to fit:
Zoomed to fit:
Zoomed to fit original size:
Notes:
While fiddling originally with a square image of 300×300 pixels, I became aware that rotating a non-square rectangle may result in a bounding box with a different aspect-ratio than the original. Hence, an additional translation might be desirable to align the scaled output in the original bounding box again. I switched to a non-square sample image of 300×200 pixels to illustrate this.
With the fit in calculations, the translations before/after rotation are actually obsolete. The result will be translated in any case to the intended position.
Instead of Qt::gray, the “background color” (i.e. the color the QPixmap is filled with initially) might be set complete transparently. I decided to stick to the Qt::gray for illustration.
I have a custom QGraphicsWidgets which paints a few items and also contains some children proxy widgets:
//Constructor adds a child proxy button
TestWidget::TestWidget(QJsonObject testDefinition, QJsonObject testStatus, QString parentSequenceID, QGraphicsWidget *parent):
m_parentID(parentSequenceID),
m_testStatus(testStatus),
m_testDefinition(testDefinition)
{
Q_UNUSED(parent);
m_name = m_testDefinition[displayNameStr].toString();
m_status = m_testStatus[resultStr].toObject()[resultStr].toString();
m_id = m_testDefinition[idStr].toString();
m_layout = new QGraphicsLinearLayout(Qt::Vertical, this);
//Add the pause/resume button
auto *proxyPauseAbortButton = new QGraphicsProxyWidget(this);
proxyPauseAbortButton->setWidget(new QPushButton(tr("Pause")));
proxyPauseAbortButton->moveBy(20, 40);
//Add the progress bar
auto * proxyTestProgressBar = new QGraphicsProxyWidget(this);
QProgressBar * testProgressBar = new QProgressBar();
testProgressBar->setOrientation(Qt::Horizontal);
testProgressBar->setRange(0, 100); // Let's say it goes from 0 to 100
testProgressBar->setValue(10); // With a current value of 10
proxyTestProgressBar->setWidget(testProgressBar);
proxyTestProgressBar->moveBy(20, 80);
//Add the html view
auto * proxyTestHtmlView = new QGraphicsProxyWidget(this);
QWebEngineView * testHtmlView = new QWebEngineView();
testHtmlView->load(QUrl(QStringLiteral("https://www.google.com/")));
proxyTestHtmlView->setWidget(testHtmlView);
proxyTestHtmlView->moveBy(20, 120);
}
//Paint function draws a border, shapes, and text
void TestWidget::paint(QPainter *painter,
const QStyleOptionGraphicsItem *option, QWidget *widget /*= 0*/)
{
Q_UNUSED(widget);
Q_UNUSED(option);
QRectF frame(QPointF(0,0), geometry().size());
QGradientStops stops;
//Draw border
painter->drawRoundedRect(boundingRect(), 5.0, 5.0);
//Name of the test
painter->drawText(40, 20, m_name);
//Status of test
QFont font = painter->font() ;
font.setPointSize(14);
painter->setFont(font);
painter->drawText(600, 20, m_status);
//Arrow button
QPolygonF poly;
poly << QPointF(5, 10) << QPointF(25, 10) << QPointF(15, 20 )<< QPointF(5, 10);
painter->setBrush(Qt::black);
painter->drawPolygon(poly, Qt::OddEvenFill);
}
My question is how would you add each component (drawing/widget) to a layout, and at what time would it be appropriate to do so? The term widgets refers to the QPushButton, QProgressBar, and QWebEngineView. Drawings refers to the shapes and text in the paint function.
Here is a sketch of how I would like the custom widget to look like:
I have QGraphicsScene, which size is 62450x4750. Somethimes I need to make screenshot of whole scene and save it to file. I tried like this:
QPixmap wholeScene(scene.sceneRect().size().toSize());
{
QPainter wholeScenePainter(&wholeScene);
scene.render(&wholeScenePainter);
}
// saving pixmap
or
QPixmap wholeScene(scene.sceneRect().size().toSize());
{
QPainter wholeScenePainter(&wholeScene);
int x = 0;
int portion = 32768; //
while( x < scene.sceneRect().width()) {
int width = scene.sceneRect().width() - x > portion ? portion : scene.sceneRect().width() - x;
QRect rect(x, 0, width, scene.sceneRect().height());
scene.render(&wholeScenePainter, rect, rect);
x += width;
}
}
// saving pixmap
or
QPixmap wholeScene(scene.sceneRect().size().toSize());
{
QPainter wholeScenePainter(&wholeScene);
int x = 0;
int portion = 4096;
while( x < scene.sceneRect().width()) {
int width = scene.sceneRect().width() - x > portion ? portion : scene.sceneRect().width() - x;
QRect rect(x, 0, width, scene.sceneRect().height());
QPixmap temp(rect.size());
QPainter p(&temp);
scene.render(&p, QRect(0, 0, rect.width(), rect.height()), rect);
wholeScenePainter.drawPixmap(x,0, temp);
//temp.save(QString("print%1.png").arg(QString::number(x)), "PNG");
x += width;
}
}
// saving pixmap
But every time I get the Image(Pixmap) cuted by width on 32768 px.
According to the documentation, QPainter does not support coordinates larger than +/- 32768. This does not appear to be fixed in Qt 5 either.
Maybe you can solve this by rendering the scene in multiple passes, e.g. through translation and clipping. You can render the scene in multiple blocks of max 32768x32768 pixels and put them in the proper position in the final image.
Assume you have created the following custom QGraphicsRectItem in C++:
class MyCustomItem : public QGraphicsRectItem
{
public:
MyCustomItem(MyCustomItem* a_Parent = 0);
virtual ~MyCustomItem();
// specific methods
private:
// specific data
};
Assume also that you have defined in a QML script an ApplicationWindow:
// main.qml
import QtQuick 2.4
import QtQuick.Controls 1.3
import QtQuick.Window 2.0
ApplicationWindow {
id: myWindow
title: qsTr("My Window")
width: 640
height: 480
visible: true
}
The simple task I would like to do is to display an instance of MyCustomItem in that ApplicationWindow. I wanted to do the following:
// part of main.cpp
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
MyCustomItem* myItem;
engine.rootContext()->setContextProperty("MyCustomItem", myItem);
return app.exec();
}
But of course this doesn't work, because MyCustomItem is neither a QObject nor a QVariant. I don't want my item to be anything else than a QGraphicsRectItem. Isn't that possible to display that graphics item? That should be simple as hell, shouldn't it? Is there a way with QDeclarativeItem or something? I can't find how to solve this problem, that's very frustrating. Would I implement my application with "normal" Qt, the problem would already be solved, because in this case you have a scene, and the scene has a member method addItem() and I don't need to do complicated stuff to add my custom graphics item to my scene. Do I have to wrap this item in a QDeclarativeItem or a QObject in order to get the thing done? That would be so awful, in my opinion. Aren't there better options?
EDIT
Can that be that QGraphicsRectItem is not the right class to inherit from and that something like QQuickPaintedItem (as suggested in the comments) would be more appropriate?
I can't speak for Qt 4, but in Qt 5, you have several options for custom drawing:
QQuickPaintedItem
A QPainter-based QQuickItem. This sounds the closest to what you want. A snippet from the documentation of one of the examples:
void TextBalloon::paint(QPainter *painter)
{
QBrush brush(QColor("#007430"));
painter->setBrush(brush);
painter->setPen(Qt::NoPen);
painter->setRenderHint(QPainter::Antialiasing);
painter->drawRoundedRect(0, 0, boundingRect().width(), boundingRect().height() - 10, 10, 10);
if (rightAligned)
{
const QPointF points[3] = {
QPointF(boundingRect().width() - 10.0, boundingRect().height() - 10.0),
QPointF(boundingRect().width() - 20.0, boundingRect().height()),
QPointF(boundingRect().width() - 30.0, boundingRect().height() - 10.0),
};
painter->drawConvexPolygon(points, 3);
}
else
{
const QPointF points[3] = {
QPointF(10.0, boundingRect().height() - 10.0),
QPointF(20.0, boundingRect().height()),
QPointF(30.0, boundingRect().height() - 10.0),
};
painter->drawConvexPolygon(points, 3);
}
}
Canvas
JavaScript-based drawing QML type with an HTML5-like API. A snippet from one of the examples:
Canvas {
id: canvas
width: 320
height: 250
antialiasing: true
property color strokeStyle: Qt.darker(fillStyle, 1.2)
property color fillStyle: "#6400aa"
property int lineWidth: 2
property int nSize: nCtrl.value
property real radius: rCtrl.value
property bool fill: true
property bool stroke: false
property real px: width/2
property real py: height/2 + 10
property real alpha: 1.0
onRadiusChanged: requestPaint();
onLineWidthChanged: requestPaint();
onNSizeChanged: requestPaint();
onFillChanged: requestPaint();
onStrokeChanged: requestPaint();
onPaint: squcirle();
function squcirle() {
var ctx = canvas.getContext("2d");
var N = canvas.nSize;
var R = canvas.radius;
N=Math.abs(N);
var M=N;
if (N>100) M=100;
if (N<0.00000000001) M=0.00000000001;
ctx.save();
ctx.globalAlpha =canvas.alpha;
ctx.fillStyle = "white";
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.strokeStyle = canvas.strokeStyle;
ctx.fillStyle = canvas.fillStyle;
ctx.lineWidth = canvas.lineWidth;
ctx.beginPath();
var i = 0, x, y;
for (i=0; i<(2*R+1); i++){
x = Math.round(i-R) + canvas.px;
y = Math.round(Math.pow(Math.abs(Math.pow(R,M)-Math.pow(Math.abs(i-R),M)),1/M)) + canvas.py;
if (i == 0)
ctx.moveTo(x, y);
else
ctx.lineTo(x, y);
}
for (i=(2*R); i<(4*R+1); i++){
x =Math.round(3*R-i)+canvas.px;
y = Math.round(-Math.pow(Math.abs(Math.pow(R,M)-Math.pow(Math.abs(3*R-i),M)),1/M)) + canvas.py;
ctx.lineTo(x, y);
}
ctx.closePath();
if (canvas.stroke) {
ctx.stroke();
}
if (canvas.fill) {
ctx.fill();
}
ctx.restore();
}
}
QSGGeometryNode
As mentioned in this answer, you could take advantage of the Qt Quick Scene Graph. A snippet from one of the examples:
QSGNode *BezierCurve::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
{
QSGGeometryNode *node = 0;
QSGGeometry *geometry = 0;
if (!oldNode) {
node = new QSGGeometryNode;
geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), m_segmentCount);
geometry->setLineWidth(2);
geometry->setDrawingMode(GL_LINE_STRIP);
node->setGeometry(geometry);
node->setFlag(QSGNode::OwnsGeometry);
QSGFlatColorMaterial *material = new QSGFlatColorMaterial;
material->setColor(QColor(255, 0, 0));
node->setMaterial(material);
node->setFlag(QSGNode::OwnsMaterial);
} else {
node = static_cast<QSGGeometryNode *>(oldNode);
geometry = node->geometry();
geometry->allocate(m_segmentCount);
}
QRectF bounds = boundingRect();
QSGGeometry::Point2D *vertices = geometry->vertexDataAsPoint2D();
for (int i = 0; i < m_segmentCount; ++i) {
qreal t = i / qreal(m_segmentCount - 1);
qreal invt = 1 - t;
QPointF pos = invt * invt * invt * m_p1
+ 3 * invt * invt * t * m_p2
+ 3 * invt * t * t * m_p3
+ t * t * t * m_p4;
float x = bounds.x() + pos.x() * bounds.width();
float y = bounds.y() + pos.y() * bounds.height();
vertices[i].set(x, y);
}
node->markDirty(QSGNode::DirtyGeometry);
return node;
}
QQuickWidget
If you really want to use QGraphicsItem subclasses, you could go the opposite direction, and have a widget-based app that contains certain "Qt Quick Widgets", though this is not optimal (see Qt Weekly #16: QQuickWidget for more information).
I am trying to construct an equilateral triangle with the following code, but I am not seeing what I would expect to.
I would expect to see a triangle drawn to the stage, but I don't see one.
I think there must be something wrong in terms of the location of the tri sprite on the screen.
public class test_drawing_triangle extends Sprite
{
public function test_drawing_triangle()
{
var tri:Sprite = new Sprite;
var nextx:int;
var nexty:int;
var prevx:int;
var prevy:int;
var angle:Number;
var radius:Number;
var deg:int;
var i:int;
radius = 10;
// tri.x = stage.stageWidth / 2;
tri.y = 50;
tri.graphics.clear();
tri.graphics.beginFill(0x000000, 0.5);
tri.graphics.moveTo(0,0);
for(deg = 0; deg < 360; deg += 120)
{
angle = deg * Math.PI / 180;
nextx = Math.cos(angle) * radius;
nexty = Math.sin(angle) * radius;
tri.graphics.lineTo(nextx, nexty);
}
tri.graphics.endFill();
addChild(tri);
}
}
UPDATE:
I can now see the triangle but it is not filled in.
It seems to have the generally-correct shape, but I would expect for it be 3 sided, rather than 4.
If anyone could take a sec to compile this and look at what I am describing it would really help.
I'm not sure if I understand what you're trying to do, but if you want to have the circles at the corners of the triangle. than you need to change the
tri.graphics.drawCircle(0, 0, 2);
to
tri.graphics.drawCircle(nextx, nexty, 2);
drawCircle takes absolute x,y and doesn't care about the moveTo
EDIT - use this code in place of your loop
deg = 30;
angle = (deg * Math.PI) / 180.0;
nextx = Math.cos(angle) * radius;
nexty = Math.sin(angle) * radius;
(tri.graphics as Graphics).moveTo(nextx, nexty);
for(deg = 150; deg < 420; deg += 120)
{
angle = (deg * Math.PI) / 180.0;
nextx = Math.cos(angle) * radius;
nexty = Math.sin(angle) * radius;
(tri.graphics as Graphics).lineTo(nextx, nexty);
}
This code looks like its drawing three circles centered on the points of your triangle. If that's the case, then replace
tri.graphics.moveTo(nextx, nexty);
tri.graphics.drawCircle(0, 0, 2);
with
tri.graphics.lineTo(nextx, nexty);
If that's not the case, please specify what it is you are seeing so we might have a better idea of what's gone wrong.
Is there are particular reason why you are using angles to draw the triangle?
If I were to do this, I'd simply hard code a unit sized equilateral triangle (defined as three 3d points) once and then use scale and translation operations to put it in the correct size and position.