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Allow monochrome images to be cut and pasted as mosaic sixels

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For cut and copy sixels are converted to a monochrome image; unset sixels
are black and set sixels are white. Alphanumerics and control codes are
ignored. Held mosaics are not considered.

For paste a clipboard with only an image is converted to black and white
for unset and set sixels. This only works reliably with fully-black and
fully-white pixels.
This commit is contained in:
G.K.MacGregor
2024-07-07 13:20:47 +01:00
parent 54bdf1783a
commit fbdde54fe4
2 changed files with 103 additions and 1 deletions
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70
levelonecommands.cpp
View File

@@ -21,6 +21,7 @@
#include <QByteArray>
#include <QByteArrayList>
#include <QClipboard>
#include <QImage>
#include <QMimeData>
#include <QRegularExpression>
@@ -605,6 +606,75 @@ PasteCommand::PasteCommand(TeletextDocument *teletextDocument, int pageCharSet,
m_pasteBottomRow = m_pasteTopRow + m_clipboardDataHeight - 1;
m_pasteRightColumn = m_pasteLeftColumn + m_clipboardDataWidth - 1;
}
} else if (mimeData->hasImage()) {
QImage imageData = qvariant_cast<QImage>(mimeData->imageData());
m_plainText = false;
// Round up when dividing pixel size into character cell size
m_clipboardDataHeight = (imageData.height() + 2) / 3;
m_clipboardDataWidth = (imageData.width() + 1) / 2;
// Format_MonoLSB reverses the bits which makes them easier to shuffle into sixels
if (imageData.depth() == 1)
imageData.convertTo(QImage::Format_MonoLSB);
else
// Only pure black and white images convert reliably this way...
imageData = imageData.convertToFormat(QImage::Format_MonoLSB, QVector<QRgb>{0x000000ff, 0xffffffff});
for (int r=0; r<m_clipboardDataHeight; r++)
m_pastingCharacters.append(QByteArray(m_clipboardDataWidth, 0x00));
// Directly read the pixel-bits and convert them to sixels with some funky bit manipulation
for (int y=0; y<imageData.height(); y++) {
const unsigned char *bytePointer = imageData.constScanLine(y);
// Three rows of sixels per character cell
const int r = y / 3;
// Where to shuffle the bits into the top, middle or bottom row of sixels
// Yes it does put the bottom right sixel into bit 5 instead of bit 6;
// this gets remedied further on
const int yShift = (y % 3) * 2;
// The loop does eight horizontal pixels into four character cells at a time
for (int x=0; x<imageData.width(); x+=8) {
const unsigned char byteScanned = *bytePointer;
const int c = x / 2;
m_pastingCharacters[r][c] = m_pastingCharacters[r][c] | ((byteScanned & 0x03) << yShift);
// Since we're doing four character cells at a time, we need to exit the loop
// early before we go out of bounds.
// Yes it does leave an undefined last column of sixels from images that are an
// odd numbered number of pixels wide; this gets remedied further on
if (x + 2 >= imageData.width())
continue;
m_pastingCharacters[r][c+1] = m_pastingCharacters[r][c+1] | (((byteScanned >> 2) & 0x03) << yShift);
if (x + 4 >= imageData.width())
continue;
m_pastingCharacters[r][c+2] = m_pastingCharacters[r][c+2] | (((byteScanned >> 4) & 0x03) << yShift);
if (x + 6 >= imageData.width())
continue;
m_pastingCharacters[r][c+3] = m_pastingCharacters[r][c+3] | (((byteScanned >> 6) & 0x03) << yShift);
bytePointer++;
}
}
for (int r=0; r<m_clipboardDataHeight; r++) {
for (int c=0; c<m_clipboardDataWidth; c++)
if (m_pastingCharacters.at(r).at(c) & 0x20)
// If bit 5 was set, correct this to bit 6
// but we keep bit 5 set as all mosaic characters have bit 5 set
m_pastingCharacters[r][c] = m_pastingCharacters.at(r).at(c) | 0x40;
else
// Set bit 5 to have it recognised as a mosaic character
m_pastingCharacters[r][c] = m_pastingCharacters.at(r).at(c) | 0x20;
// If image was an odd numbered width, neutralise the undefined sixels
// on the right half
if (imageData.width() & 0x01)
m_pastingCharacters[r][m_clipboardDataWidth-1] = m_pastingCharacters.at(r).at(m_clipboardDataWidth-1) & 0x35;
}
if (!m_selectionActive) {
m_pasteBottomRow = m_row + m_clipboardDataHeight - 1;
m_pasteRightColumn = m_column + m_clipboardDataWidth - 1;
}
}
if (m_clipboardDataWidth == 0 || m_clipboardDataHeight == 0)

34
mainwidget.cpp
View File

@@ -26,6 +26,7 @@
#include <QGraphicsProxyWidget>
#include <QGraphicsScene>
#include <QGraphicsSceneEvent>
#include <QImage>
#include <QKeyEvent>
#include <QMenu>
#include <QMimeData>
@@ -385,6 +386,7 @@ void TeletextWidget::selectionToClipboard()
{
QByteArray nativeData;
QString plainTextData;
QImage *imageData = nullptr;
QClipboard *clipboard = QApplication::clipboard();
nativeData.resize(2 + m_teletextDocument->selectionWidth() * m_teletextDocument->selectionHeight());
@@ -393,7 +395,7 @@ void TeletextWidget::selectionToClipboard()
plainTextData.reserve((m_teletextDocument->selectionWidth()+1) * m_teletextDocument->selectionHeight() - 1);
int i=2;
int i = 2;
for (int r=m_teletextDocument->selectionTopRow(); r<=m_teletextDocument->selectionBottomRow(); r++) {
for (int c=m_teletextDocument->selectionLeftColumn(); c<=m_teletextDocument->selectionRightColumn(); c++) {
@@ -403,6 +405,31 @@ void TeletextWidget::selectionToClipboard()
plainTextData.append(keymapping[m_pageDecode.level1CharSet(r, c)].key(m_teletextDocument->currentSubPage()->character(r, c), QChar(m_teletextDocument->currentSubPage()->character(r, c))));
else
plainTextData.append(' ');
if (m_pageDecode.level1MosaicAttribute(r, c) && m_teletextDocument->currentSubPage()->character(r, c) & 0x20) {
// A first mosaic character was found so create the image "just in time"
if (imageData == nullptr) {
imageData = new QImage(m_teletextDocument->selectionWidth() * 2, m_teletextDocument->selectionHeight() * 3, QImage::Format_Mono);
imageData->fill(0);
}
const int ix = (c - m_teletextDocument->selectionLeftColumn()) * 2;
const int iy = (r - m_teletextDocument->selectionTopRow()) * 3;
if (m_teletextDocument->currentSubPage()->character(r, c) & 0x01)
imageData->setPixel(ix, iy, 1);
if (m_teletextDocument->currentSubPage()->character(r, c) & 0x02)
imageData->setPixel(ix+1, iy, 1);
if (m_teletextDocument->currentSubPage()->character(r, c) & 0x04)
imageData->setPixel(ix, iy+1, 1);
if (m_teletextDocument->currentSubPage()->character(r, c) & 0x08)
imageData->setPixel(ix+1, iy+1, 1);
if (m_teletextDocument->currentSubPage()->character(r, c) & 0x10)
imageData->setPixel(ix, iy+2, 1);
if (m_teletextDocument->currentSubPage()->character(r, c) & 0x40)
imageData->setPixel(ix+1, iy+2, 1);
}
}
plainTextData.append('\n');
@@ -411,6 +438,11 @@ void TeletextWidget::selectionToClipboard()
QMimeData *mimeData = new QMimeData();
mimeData->setData("application/x-teletext", nativeData);
mimeData->setText(plainTextData);
if (imageData != nullptr) {
mimeData->setImageData(*imageData);
delete imageData;
}
clipboard->setMimeData(mimeData);
}