Issue #118: Refactoring of forms

Pdf4QtLibWidgets/sources/pdftexteditpseudowidget.h

@@ -0,0 +1,217 @@
+//    Copyright (C) 2022 Jakub Melka
+//
+//    This file is part of PDF4QT.
+//
+//    PDF4QT is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Lesser General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    with the written consent of the copyright owner, any later version.
+//
+//    PDF4QT is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public License
+//    along with PDF4QT. If not, see <https://www.gnu.org/licenses/>.
+
+#ifndef PDFTEXTEDITPSEUDOWIDGET_H
+#define PDFTEXTEDITPSEUDOWIDGET_H
+
+#include "pdfglobal.h"
+#include "pdfform.h"
+
+#include <QRectF>
+#include <QColor>
+
+class QWidget;
+class QKeyEvent;
+
+namespace pdf
+{
+
+/// "Pseudo" widget, which is emulating text editor, which can be single line, or multiline.
+/// Passwords can also be edited and editor can be read only.
+class PDFTextEditPseudowidget
+{
+public:
+    explicit PDFTextEditPseudowidget(PDFFormField::FieldFlags flags);
+
+    void shortcutOverrideEvent(QWidget* widget, QKeyEvent* event);
+    void keyPressEvent(QWidget* widget, QKeyEvent* event);
+
+    inline bool isReadonly() const { return m_flags.testFlag(PDFFormField::ReadOnly); }
+    inline bool isMultiline() const { return m_flags.testFlag(PDFFormField::Multiline); }
+    inline bool isPassword() const { return m_flags.testFlag(PDFFormField::Password); }
+    inline bool isFileSelect() const { return m_flags.testFlag(PDFFormField::FileSelect); }
+    inline bool isComb() const { return m_flags.testFlag(PDFFormField::Comb); }
+
+    inline bool isEmpty() const { return m_editText.isEmpty(); }
+    inline bool isTextSelected() const { return !isEmpty() && getSelectionLength() > 0; }
+    inline bool isWholeTextSelected() const { return !isEmpty() && getSelectionLength() == m_editText.length(); }
+
+    inline int getTextLength() const { return m_editText.length(); }
+    inline int getSelectionLength() const { return m_selectionEnd - m_selectionStart; }
+
+    inline int getPositionCursor() const { return m_positionCursor; }
+    inline int getPositionStart() const { return 0; }
+    inline int getPositionEnd() const { return getTextLength(); }
+
+    inline void clearSelection() { m_selectionStart = m_selectionEnd = 0; }
+
+    inline const QString& getText() const { return m_editText; }
+    inline QString getSelectedText() const { return m_editText.mid(m_selectionStart, getSelectionLength()); }
+
+    /// Sets (updates) text selection
+    /// \param startPosition From where we are selecting text
+    /// \param selectionLength Selection length (positive - to the right, negative - to the left)
+    void setSelection(int startPosition, int selectionLength);
+
+    /// Moves cursor position. It behaves as usual in text boxes,
+    /// when user moves the cursor. If \p select is true, then
+    /// selection is updated.
+    /// \param position New position of the cursor
+    /// \param select Select text when moving the cursor?
+    void setCursorPosition(int position, bool select);
+
+    /// Sets text content of the widget. This functions sets the text,
+    /// even if widget is readonly.
+    /// \param text Text to be set
+    void setText(const QString& text);
+
+    /// Sets widget appearance, such as font, font size, color, text alignment,
+    /// and rectangle, in which widget resides on page (in page coordinates)
+    /// \param appearance Appearance
+    /// \param textAlignment Text alignment
+    /// \param rect Widget rectangle in page coordinates
+    /// \param maxTextLength Maximal text length
+    void setAppearance(const PDFAnnotationDefaultAppearance& appearance,
+                       Qt::Alignment textAlignment,
+                       QRectF rect,
+                       int maxTextLength);
+
+    /// Sets widget appearance, such as font, font size, color, text alignment,
+    /// and rectangle, in which widget resides on page (in page coordinates)
+    /// \param font Font
+    /// \param textAlignment Text alignment
+    /// \param rect Widget rectangle in page coordinates
+    /// \param maxTextLength Maximal text length
+    /// \param textColor Color
+    void setAppearance(const QFont& font,
+                       Qt::Alignment textAlignment,
+                       QRectF rect,
+                       int maxTextLength,
+                       QColor textColor);
+
+    void performCut();
+    void performCopy();
+    void performPaste();
+    void performClear();
+    void performSelectAll();
+    void performBackspace();
+    void performDelete();
+    void performRemoveSelectedText();
+    void performInsertText(const QString& text);
+
+    /// Draw text edit using given parameters
+    /// \param parameters Parameters
+    void draw(AnnotationDrawParameters& parameters, bool edit) const;
+
+    /// Returns valid cursor position retrieved from position in the widget.
+    /// \param point Point in page coordinate space
+    /// \param edit Are we using edit transformations?
+    /// \returns Cursor position
+    int getCursorPositionFromWidgetPosition(const QPointF& point, bool edit) const;
+
+    inline int getCursorForward(QTextLayout::CursorMode mode) const { return getNextPrevCursorPosition(getSingleStepForward(), mode); }
+    inline int getCursorBackward(QTextLayout::CursorMode mode) const { return getNextPrevCursorPosition(getSingleStepBackward(), mode); }
+    inline int getCursorCharacterForward() const { return getCursorForward(QTextLayout::SkipCharacters); }
+    inline int getCursorCharacterBackward() const { return getCursorBackward(QTextLayout::SkipCharacters); }
+    inline int getCursorWordForward() const { return getCursorForward(QTextLayout::SkipWords); }
+    inline int getCursorWordBackward() const { return getCursorBackward(QTextLayout::SkipWords); }
+    inline int getCursorDocumentStart() const { return (getSingleStepForward() > 0) ? getPositionStart() : getPositionEnd(); }
+    inline int getCursorDocumentEnd() const { return (getSingleStepForward() > 0) ? getPositionEnd() : getPositionStart(); }
+    inline int getCursorLineStart() const { return (getSingleStepForward() > 0) ? getCurrentLineTextStart() : getCurrentLineTextEnd(); }
+    inline int getCursorLineEnd() const { return (getSingleStepForward() > 0) ? getCurrentLineTextEnd() : getCurrentLineTextStart(); }
+    inline int getCursorNextLine() const { return getCurrentLineTextEnd(); }
+    inline int getCursorPreviousLine() const { return getNextPrevCursorPosition(getCurrentLineTextStart(), -1, QTextLayout::SkipCharacters); }
+
+    const QRectF& getWidgetRect() const { return m_widgetRect; }
+    QFont getFont() const { return m_textLayout.font(); }
+    QColor getFontColor() const { return m_textColor; }
+
+private:
+    /// This function does following things:
+    ///     1) Clamps edit text to fit maximum length
+    ///     2) Creates display string from edit string
+    ///     3) Updates text layout
+    void updateTextLayout();
+
+    /// Returns single step forward, which is determined
+    /// by cursor move style and layout direction.
+    int getSingleStepForward() const;
+
+    /// Returns single step backward, which is determined
+    /// by cursor move style and layout direction.
+    int getSingleStepBackward() const { return -getSingleStepForward(); }
+
+    /// Returns next/previous position, by number of steps,
+    /// using given cursor mode (skipping characters or whole words).
+    /// \param steps Number of steps to proceed (can be negative number)
+    /// \param mode Skip mode - letters or words?
+    int getNextPrevCursorPosition(int steps, QTextLayout::CursorMode mode) const { return getNextPrevCursorPosition(m_positionCursor, steps, mode); }
+
+    /// Returns next/previous position from reference cursor position, by number of steps,
+    /// using given cursor mode (skipping characters or whole words).
+    /// \param referencePosition Reference cursor position
+    /// \param steps Number of steps to proceed (can be negative number)
+    /// \param mode Skip mode - letters or words?
+    int getNextPrevCursorPosition(int referencePosition, int steps, QTextLayout::CursorMode mode) const;
+
+    /// Returns current line text start position
+    int getCurrentLineTextStart() const;
+
+    /// Returns current line text end position
+    int getCurrentLineTextEnd() const;
+
+    /// Creates text box transform matrix, which transforms from
+    /// widget space to page space.
+    /// \param edit Create matrix for text editing?
+    QTransform createTextBoxTransformMatrix(bool edit) const;
+
+    /// Returns vector of cursor positions (which may be not equal
+    /// to edit string length, because edit string can contain surrogates,
+    /// or graphemes, which are single glyphs, but represented by more
+    /// 16-bit unicode codes).
+    std::vector<int> getCursorPositions() const;
+
+    int getCursorLineUp() const;
+    int getCursorLineDown() const;
+
+    PDFFormField::FieldFlags m_flags;
+
+    /// Text edited by the user
+    QString m_editText;
+
+    /// Text, which is displayed. It can differ from text
+    /// edited by user, in case password is being entered.
+    QString m_displayText;
+
+    /// Text layout
+    QTextLayout m_textLayout;
+
+    /// Character for displaying passwords
+    QChar m_passwordReplacementCharacter;
+
+    int m_selectionStart;
+    int m_selectionEnd;
+    int m_positionCursor;
+    int m_maxTextLength;
+
+    QRectF m_widgetRect;
+    QColor m_textColor;
+};
+
+}   // namespace pdf
+
+#endif // PDFTEXTEDITPSEUDOWIDGET_H