vial/src/main/python/keyboard_widget.py

from PyQt5.QtGui import QPainter, QColor, QPainterPath, QTransform, QBrush, QPolygonF
from PyQt5.QtWidgets import QWidget, QToolTip
from PyQt5.QtCore import Qt, QSize, QRect, QPointF, pyqtSignal, QEvent

from constants import KEY_WIDTH, KEY_SPACING, KEY_HEIGHT, KEYBOARD_WIDGET_PADDING


class KeyWidget:

    def __init__(self, desc):
        self.desc = desc
        self.text = ""
        self.tooltip = ""

        self.rotation_x = (KEY_WIDTH + KEY_SPACING) * desc.rotation_x
        self.rotation_y = (KEY_HEIGHT + KEY_SPACING) * desc.rotation_y
        self.rotation_angle = desc.rotation_angle

        self.x = (KEY_WIDTH + KEY_SPACING) * desc.x
        self.y = (KEY_HEIGHT + KEY_SPACING) * desc.y
        self.w = (KEY_WIDTH + KEY_SPACING) * desc.width - KEY_SPACING
        self.h = (KEY_HEIGHT + KEY_SPACING) * desc.height - KEY_SPACING

        self.rect = QRect(self.x, self.y, self.w, self.h)

        self.has2 = desc.width2 != desc.width or desc.height2 != desc.height or desc.x2 != 0 or desc.y2 != 0

        self.x2 = self.x + (KEY_WIDTH + KEY_SPACING) * desc.x2
        self.y2 = self.y + (KEY_WIDTH + KEY_SPACING) * desc.y2
        self.w2 = (KEY_WIDTH + KEY_SPACING) * desc.width2 - KEY_SPACING
        self.h2 = (KEY_HEIGHT + KEY_SPACING) * desc.height2 - KEY_SPACING

        self.bbox = self.calculate_bbox()
        self.polygon = QPolygonF(self.bbox + [self.bbox[0]])
        self.draw_path = self.calculate_draw_path()

    def calculate_bbox(self):
        x1 = self.x
        y1 = self.y
        x2 = self.x + self.w
        y2 = self.y + self.h
        points = [(x1, y1), (x1, y2), (x2, y2), (x2, y1)]
        bbox = []
        for p in points:
            t = QTransform()
            t.translate(KEYBOARD_WIDGET_PADDING, KEYBOARD_WIDGET_PADDING)
            t.translate(self.rotation_x, self.rotation_y)
            t.rotate(self.rotation_angle)
            t.translate(-self.rotation_x, -self.rotation_y)
            p = t.map(QPointF(p[0], p[1]))
            bbox.append(p)
        return bbox

    def calculate_draw_path(self):
        path = QPainterPath()
        path.addRect(int(self.x), int(self.y), int(self.w), int(self.h))

        # second part only considered if different from first
        if self.has2:
            path2 = QPainterPath()
            path2.addRect(int(self.x2), int(self.y2), int(self.w2), int(self.h2))
            path = path.united(path2)

        return path

    def setText(self, text):
        self.text = text

    def setToolTip(self, tooltip):
        self.tooltip = tooltip


class KeyboardWidget(QWidget):

    clicked = pyqtSignal(KeyWidget)

    def __init__(self):
        super().__init__()
        self.setMouseTracking(True)

        self.keys = []
        self.width = self.height = 0
        self.active_key = None

    def set_keys(self, keys):
        self.keys = []
        for key in keys:
            self.keys.append(KeyWidget(key))
        self.calculate_size()
        self.update()

    def calculate_size(self):
        max_w = max_h = 0

        for key in self.keys:
            p = key.polygon.boundingRect().bottomRight()
            max_w = max(max_w, p.x())
            max_h = max(max_h, p.y())

        self.width = max_w + 2 * KEYBOARD_WIDGET_PADDING
        self.height = max_h + 2 * KEYBOARD_WIDGET_PADDING

    def paintEvent(self, event):
        qp = QPainter()
        qp.begin(self)
        qp.setRenderHint(QPainter.Antialiasing)

        # add a little padding
        qp.translate(KEYBOARD_WIDGET_PADDING, KEYBOARD_WIDGET_PADDING)

        # for regular keycaps
        regular_pen = qp.pen()
        regular_pen.setColor(QColor("black"))
        qp.setPen(regular_pen)

        regular_brush = QBrush()
        regular_brush.setColor(QColor("white"))
        regular_brush.setStyle(Qt.SolidPattern)
        qp.setBrush(regular_brush)

        # for currently selected keycap
        active_pen = qp.pen()
        active_pen.setColor(QColor("white"))

        active_brush = QBrush()
        active_brush.setColor(QColor("black"))
        active_brush.setStyle(Qt.SolidPattern)

        for idx, key in enumerate(self.keys):
            qp.save()
            qp.translate(key.rotation_x, key.rotation_y)
            qp.rotate(key.rotation_angle)
            qp.translate(-key.rotation_x, -key.rotation_y)

            if self.active_key == key:
                qp.setPen(active_pen)
                qp.setBrush(active_brush)

            # draw the keycap
            qp.drawPath(key.draw_path)

            # draw the legend
            qp.drawText(key.rect, Qt.AlignCenter, key.text)

            qp.restore()

        qp.end()

    def minimumSizeHint(self):
        return QSize(self.width, self.height)

    def hit_test(self, pos):
        for key in self.keys:
            if key.polygon.containsPoint(pos, Qt.OddEvenFill):
                return key
        return None

    def mousePressEvent(self, ev):
        prev_active_key = self.active_key

        self.active_key = self.hit_test(ev.pos())
        if self.active_key is not None:
            self.clicked.emit(self.active_key)

        if prev_active_key != self.active_key:
            self.update()

    def deselect(self):
        if self.active_key is not None:
            self.active_key = None
            self.update()

    def event(self, ev):
        if ev.type() == QEvent.ToolTip:
            key = self.hit_test(ev.pos())
            if key is not None:
                QToolTip.showText(ev.globalPos(), key.tooltip)
            else:
                QToolTip.hideText()
        return super().event(ev)