PySideを使って消しゴムツールを実現できそうかテスト

eraser_tool_test.py

#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2016/11/14 22:41:03 +0900>
u"""
消しゴムツールのテスト.

QPixmapに対して働く消しゴムツールを作れそうか実験。

Author : mieki256
License : CC0 / Public Domain.

"""


import sys
from PySide.QtCore import *  # NOQA
from PySide.QtGui import *   # NOQA


class MyGView(QGraphicsView):

    """Custom GraphicsView."""

    def __init__(self, *argv, **keywords):
        """init."""
        super(MyGView, self).__init__(*argv, **keywords)
        scene = QGraphicsScene(self)
        self.setScene(scene)
        scene.setBackgroundBrush(QBrush(self.get_bg_chip_image()))

        self.canvas = QPixmap("./tmp_bg_night.png")
        self.canvas_item = QGraphicsPixmapItem(self.canvas)
        scene.addItem(self.canvas_item)

        self.brush = QPixmap("./tmp_brush2.png")

        self.draw_brush()

        # self.erase_brush()
        self.erase_brush_pixmap()

    def draw_brush(self):
        u"""ブラシ画像で描画."""
        qp = QPainter()
        qp.begin(self.canvas)
        qp.setCompositionMode(QPainter.CompositionMode_SourceOver)
        x, y = 0, 0
        qp.drawPixmap(x, y, self.brush)
        qp.end()
        del qp
        self.canvas_item.setPixmap(self.canvas)

    def erase_brush_pixmap(self):
        u"""ブラシ画像(QPixmap)を消しゴムとして使う."""
        qp = QPainter()
        qp.begin(self.canvas)
        qp.setCompositionMode(QPainter.CompositionMode_DestinationOut)
        x, y = self.brush.width() + 16, 0
        qp.drawPixmap(x, y, self.brush)
        qp.end()
        del qp
        self.canvas_item.setPixmap(self.canvas)

    def erase_brush(self):
        u"""ブラシ画像(QImage)を消しゴムとして使う."""
        # QPixmap を Qimage に変換
        bim = self.brush.toImage()
        if bim.format() != QImage.Format_ARGB32:
            bim = bim.convertToFormat(QImage.Format_ARGB32)

        cim = self.canvas.toImage()
        if cim.format() != QImage.Format_ARGB32:
            cim = cim.convertToFormat(QImage.Format_ARGB32)

        # QPainter を使って描画
        qp = QPainter()
        qp.begin(cim)

        # 合成モードを指定して描画
        qp.setCompositionMode(QPainter.CompositionMode_DestinationOut)
        x, y = self.brush.width() + 16, 0
        qp.drawImage(x, y, bim)

        qp.end()
        del qp

        # キャンバス画像として再設定
        self.canvas = QPixmap.fromImage(cim)
        self.canvas_item.setPixmap(self.canvas)

    def get_bg_chip_image(self):
        u"""背景塗りつぶし用のパターンを作成して返す."""
        im = QImage(16, 16, QImage.Format_ARGB32)
        for y in range(16):
            for x in range(16):
                c = 248 - 48 * ((x / 8 + y / 8) % 2)
                col = QColor(c, c, c, 255)
                im.setPixel(x, y, col.rgba())
        return im


class MyWidget(QWidget):

    """main widget."""

    def __init__(self, *argv, **keywords):
        """init."""
        super(MyWidget, self).__init__(*argv, **keywords)
        l = QVBoxLayout()
        self.gview = MyGView(self)
        l.addWidget(self.gview)
        self.setLayout(l)


def main():
    """Main."""
    app = QApplication(sys.argv)
    w = MyWidget()
    w.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

tmp_bg_night.png

tmp_brush2.png