Working scale and zoom

imagescrollareagl.cpp

@@ -6,6 +6,25 @@
 #include <QOpenGLPixelTransferOptions>
 #include <QGridLayout>
 
+void setScrollRange(QScrollBar *scrollBar, int newRange)
+{
+    int page = scrollBar->pageStep();
+    int pos = scrollBar->value() + page/2;
+    int range = scrollBar->maximum() + page;
+    float relPos = (float)pos/(float)range;
+
+    scrollBar->setRange(0, newRange - page);
+    scrollBar->setValue(relPos*newRange - page/2);
+}
+
+void setRelativePos(QScrollBar *scrollBar, float relPos)
+{
+    int page = scrollBar->pageStep();
+    int pos = scrollBar->value()+page/2;
+    int range = scrollBar->maximum()+page;
+    scrollBar->setValue(pos);
+}
+
 ImageWidget::ImageWidget(QWidget *parent) : QOpenGLWidget(parent)
 {
     setFocusPolicy(Qt::ClickFocus);
@@ -13,6 +32,8 @@ ImageWidget::ImageWidget(QWidget *parent) : QOpenGLWidget(parent)
     m_low = 0;
     m_high = 1;
     m_dx = m_dy = 0;
+    m_scale = 1.0f;
+    m_blockRepaint = false;
 }
 
 ImageWidget::~ImageWidget()
@@ -60,32 +81,64 @@ void ImageWidget::setImage(const QPixmap &pixmap)
     repaint();
 }
 
+void ImageWidget::setScale(float scale)
+{
+    m_scale = scale;
+    update();
+}
+
+void ImageWidget::blockRepaint(bool block)
+{
+    m_blockRepaint = block;
+    if(!block)update();
+}
+
 void ImageWidget::setLow(int low)
 {
     m_low = low/m_range;
-    repaint();
+    update();
 }
 
 void ImageWidget::setHigh(int high)
 {
     m_high = high/m_range;
-    repaint();
+    update();
+}
+
+void ImageWidget::setStrech(int stretch)
+{
+    m_stretch = stretch;
+    update();
 }
 
 void ImageWidget::setOffset(int dx, int dy)
 {
     m_dx = dx;
     m_dy = dy;
-    repaint();
+    update();
 }
 
 void ImageWidget::paintGL()
 {
+    if(m_blockRepaint)return;
+    qDebug() << "PAINT";
+
+    float dx = m_dx;
+    float dy = m_dy;
+    qDebug() << "dxy" << dx << dy;
+    if(width() > m_image->width()*m_scale)
+        dx = -width()*0.5f + m_image->width()*m_scale*0.5f;
+    if(height() > m_image->height()*m_scale)
+        dy = -height()*0.5f + m_image->height()*m_scale*0.5f;
+
     float s = 1.0f/(m_high-m_low);
     m_program->bind();
     m_program->setUniformValue("scale", s, -m_low*s);
     m_program->setUniformValue("viewport", (float)width(), (float)height());
-    m_program->setUniformValue("offset", m_dx, m_dy);
+    m_program->setUniformValue("offset", dx, dy);
+    m_program->setUniformValue("stretch", m_stretch);
+    m_program->setUniformValue("a", 0.1f);
+    m_program->setUniformValue("zoom", 1.0f/m_scale);
 
     m_image->bind(0);
     f->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
@@ -149,7 +202,8 @@ void ImageWidget::initializeGL()
     m_program->setUniformValue("qt_Texture0", (GLuint)0);
     m_program->setUniformValue("scale", 1.0f, 0.0f);
 
-    m_image = std::unique_ptr<QOpenGLTexture>(new QOpenGLTexture(QImage("/home/nou/Obrázky/1p6yap.jpg")));
+    m_image = std::unique_ptr<QOpenGLTexture>(new QOpenGLTexture(QOpenGLTexture::Target2D));
+    m_image->allocateStorage();
     m_image->bind(0);
     m_image->setMinificationFilter(QOpenGLTexture::LinearMipMapLinear);
     m_image->setMagnificationFilter(QOpenGLTexture::Linear);
@@ -167,6 +221,7 @@ ImageScrollAreaGL::ImageScrollAreaGL(QWidget *parent)
 
     m_verticalScrollBar = new QScrollBar(Qt::Vertical, this);
     m_horizontalScrollBar = new QScrollBar(Qt::Horizontal, this);
+    m_scale = 1.0f;
 
     layout->setSpacing(0);
     layout->addWidget(m_imageWidget, 0, 0);
@@ -203,10 +258,18 @@ ImageWidget *ImageScrollAreaGL::imageWidget()
     return m_imageWidget;
 }
 
-void ImageScrollAreaGL::updateScrollbars()
+void ImageScrollAreaGL::updateScrollbars(bool zoom)
 {
-    m_verticalScrollBar->setRange(0, m_imgHeight-m_verticalScrollBar->pageStep());
-    m_horizontalScrollBar->setRange(0, m_imgWidth-m_horizontalScrollBar->pageStep());
+    if(zoom)
+    {
+        setScrollRange(m_verticalScrollBar, m_imgHeight*m_scale);
+        setScrollRange(m_horizontalScrollBar, m_imgWidth*m_scale);
+    }
+    else
+    {
+        m_verticalScrollBar->setRange(0, m_imgHeight*m_scale - m_verticalScrollBar->pageStep());
+        m_horizontalScrollBar->setRange(0, m_imgWidth*m_scale - m_horizontalScrollBar->pageStep());
+    }
 }
 
 void ImageScrollAreaGL::resizeEvent(QResizeEvent *event)
@@ -231,6 +294,45 @@ void ImageScrollAreaGL::mousePressEvent(QMouseEvent *event)
     m_lastPos = event->pos();
 }
 
+void ImageScrollAreaGL::wheelEvent(QWheelEvent *event)
+{
+    if(event->angleDelta().y() > 0)
+        zoomIn();
+    else
+        zoomOut();
+}
+
+void ImageScrollAreaGL::zoomIn()
+{
+    if(m_scale >= 8.0f)return;
+    m_scale += 0.1f;
+    m_imageWidget->blockRepaint(true);
+    m_imageWidget->setScale(m_scale);
+    updateScrollbars(true);
+    m_imageWidget->blockRepaint(false);
+}
+
+void ImageScrollAreaGL::zoomOut()
+{
+    if(m_scale <= 0.1f)return;
+    m_scale -= 0.1f;
+    m_imageWidget->blockRepaint(true);
+    m_imageWidget->setScale(m_scale);
+    updateScrollbars(true);
+    m_imageWidget->blockRepaint(false);
+    //m_imageWidget->repaint();
+}
+
+void ImageScrollAreaGL::bestFit()
+{
+
+}
+
+void ImageScrollAreaGL::oneToOne()
+{
+
+}
+
 void ImageScrollAreaGL::scrollEvent()
 {
     qDebug() << m_horizontalScrollBar->value() << m_verticalScrollBar->value();