add a color picker dialog to palette editor

src/ui/colorpicker.cpp

@@ -0,0 +1,81 @@
+#include "colorpicker.h"
+#include "ui_colorpicker.h"
+
+#include <QtWidgets>
+
+const int zoom_box_dimensions = 7;
+
+ColorPicker::ColorPicker(QWidget *parent) :
+    QDialog(parent),
+    ui(new Ui::ColorPicker)
+{
+    ui->setupUi(this);
+
+    this->scene = new QGraphicsScene;
+
+    // listen for spacebar press to take color
+    QShortcut *takeColor = new QShortcut(Qt::Key_Space, this);
+    QObject::connect(takeColor, &QShortcut::activated, [this](){
+        timer->stop();
+        this->accept();
+    });
+
+    // need to set up a timer because there is no good way to get global mouse movement
+    // outside of the application in a cross-platform way
+    timer = new QTimer(this);
+    connect(timer, &QTimer::timeout, [this]() {
+        QPoint cursorPos = QCursor::pos();
+        if (lastCursorPos != cursorPos) {
+            lastCursorPos = cursorPos;
+            this->hover(cursorPos.x(), cursorPos.y());
+        }
+    });
+    timer->start(10);
+}
+
+ColorPicker::~ColorPicker()
+{
+    delete scene;
+    delete timer;
+    delete ui;
+}
+
+void ColorPicker::hover(int mouseX, int mouseY) {
+    QScreen *screen = QGuiApplication::primaryScreen();
+    if (const QWindow *window = windowHandle())
+        screen = window->screen();
+    if (!screen)
+        return;
+
+    // 15 X 15 box with 8x magnification = 120px square)
+    QRect zoomRect(mouseX - 7, mouseY - 7, 15, 15);
+    QPixmap grab = screen->grabWindow(0, mouseX - 7, mouseY - 7, 15, 15);
+    int pixelRatio = grab.devicePixelRatio();
+
+    // TODO: investigate for high dpi displays why text is too high res
+    grab.setDevicePixelRatio(1);
+    QPixmap magnified = grab.scaled(120, 120, Qt::KeepAspectRatio);
+
+    QPainter painter(&magnified);
+    painter.setRenderHint(QPainter::Antialiasing, false);
+    QRectF rect(55, 55, 9, 9);
+    painter.drawRect(rect);
+    painter.end();
+
+    // TODO: bounds checking?
+
+    this->color = grab.toImage().pixelColor(7 * pixelRatio, 7 * pixelRatio);
+    int r = this->color.red();
+    int g = this->color.green();
+    int b = this->color.blue();
+
+    // update the displayed color value
+    QString rgb = QString("rgb(%1, %2, %3)").arg(r).arg(g).arg(b);
+    QString stylesheet = QString("background-color: %1;").arg(rgb);
+    this->ui->frame_centralColor->setStyleSheet(stylesheet);
+
+    this->ui->label_RGB->setText(rgb);
+    this->ui->label_HEX->setText(color.name());
+
+    this->ui->viewport->setPixmap(magnified);
+}

src/ui/paletteeditor.cpp

@@ -1,8 +1,10 @@
 #include "paletteeditor.h"
 #include "ui_paletteeditor.h"
+#include "colorpicker.h"
 #include "paletteutil.h"
 #include "config.h"
 #include "log.h"
+
 #include <QFileDialog>
 #include <QMessageBox>
 
@@ -105,11 +107,40 @@ PaletteEditor::PaletteEditor(Project *project, Tileset *primaryTileset, Tileset
     this->rgbLabels.append(this->ui->label_rgb14);
     this->rgbLabels.append(this->ui->label_rgb15);
 
+    this->pickButtons.clear();
+    this->pickButtons.append(this->ui->toolButton_0);
+    this->pickButtons.append(this->ui->toolButton_1);
+    this->pickButtons.append(this->ui->toolButton_2);
+    this->pickButtons.append(this->ui->toolButton_3);
+    this->pickButtons.append(this->ui->toolButton_4);
+    this->pickButtons.append(this->ui->toolButton_5);
+    this->pickButtons.append(this->ui->toolButton_6);
+    this->pickButtons.append(this->ui->toolButton_7);
+    this->pickButtons.append(this->ui->toolButton_8);
+    this->pickButtons.append(this->ui->toolButton_9);
+    this->pickButtons.append(this->ui->toolButton_10);
+    this->pickButtons.append(this->ui->toolButton_11);
+    this->pickButtons.append(this->ui->toolButton_12);
+    this->pickButtons.append(this->ui->toolButton_13);
+    this->pickButtons.append(this->ui->toolButton_14);
+    this->pickButtons.append(this->ui->toolButton_15);
+
     // Setup edit-undo history for each of the palettes.
     for (int i = 0; i < Project::getNumPalettesTotal(); i++) {
         this->palettesHistory.append(History<PaletteHistoryItem*>());
     }
 
+    // Connect the color picker's selection to the correct color index
+    for (int i = 0; i < 16; i++) {
+        connect(this->pickButtons[i], &QToolButton::clicked, [this, i](){
+            disableSliderSignals();
+            this->pickColor(i);
+            this->setColor(i);
+            enableSliderSignals();
+        });
+        this->pickButtons[i]->setEnabled(i < (Project::getNumPalettesTotal() - 1));
+    }
+
     this->initColorSliders();
     this->setPaletteId(paletteId);
     this->commitEditHistory(this->ui->spinBox_PaletteId->value());
@@ -211,6 +242,18 @@ void PaletteEditor::setColor(int colorIndex) {
     emit this->changedPaletteColor();
 }
 
+void PaletteEditor::pickColor(int i) {
+    ColorPicker picker(this);
+    if (picker.exec() == QDialog::Accepted) {
+        QColor c = picker.getColor();
+        // TODO: round? or keep floor?
+        this->sliders[i][0]->setValue(c.red() / 8);
+        this->sliders[i][1]->setValue(c.green() / 8);
+        this->sliders[i][2]->setValue(c.blue() / 8);
+    }
+    return;
+}
+
 void PaletteEditor::on_spinBox_PaletteId_valueChanged(int paletteId) {
     this->refreshColorSliders();
     this->refreshColors();