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Manipulate image and apply RGB mask: Difference between revisions
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{{Cleanup | reason=Auto-imported from ExpressionEngine.}} | {{Cleanup | reason=Auto-imported from ExpressionEngine.}} | ||
[[Category: | [[Category:Snippets::Misc]] | ||
Small snippet showing how to take a QImage, run through its pixels and modify them based on certain conditions. | Small snippet showing how to take a QImage, run through its pixels and modify them based on certain conditions. | ||
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for (int x = rect.left(); x < rect.right(); x) | for (int x = rect.left(); x < rect.right(); x) | ||
{ | { | ||
*output = *input & | *output = *input & mask; | ||
output; | output; | ||
input''+; | input''+; | ||
Latest revision as of 11:58, 28 November 2016
| This article may require cleanup to meet the Qt Wiki's quality standards. Reason: Auto-imported from ExpressionEngine. Please improve this article if you can. Remove the {{cleanup}} tag and add this page to Updated pages list after it's clean. |
Small snippet showing how to take a QImage, run through its pixels and modify them based on certain conditions.
Here img is an input image, the application form has 4 checkboxes, which define the component of the color (ARGB) that is to be masked.
// img is the input original image
QRect rect = img->rect();
QImage *result = new QImage(wd, ht, img->format());
uint *output=0, *input = 0;
for (int y = rect.top(); y < rect.bottom(); y+'')
{
input = (uint*)img->scanLine(y - rect.top());
output = (uint*)result->scanLine(y - rect.top());
for (int x = rect.left(); x < rect.right(); x)
{
int col = *input;
if (col Qt::transparent || col Qt::color0)
{
*output''+ = *input+'';
continue;
}
QColor qcol = QColor::fromRgba(col);
if (ui->redBox->checkState() 0) qcol.setRed(0);
if (ui->greenBox->checkState() 0) qcol.setGreen(0);
if (ui->blueBox->checkState() 0) qcol.setBlue(0);
if (ui->alphaBox->checkState() 0) qcol.setAlpha(0);
*output''+ = qcol.rgba();
input+'';
}
}
// At this point result will have the modified QImage
Here is an alternative version which should be quite a bit faster, but is less readable, perhaps:
// img is the input original image
QRect rect = img->rect();
QImage *result = new QImage(wd, ht, img->format());
// Mask is suitable for colors in ARGB byte order.
uint mask = 0;
if (ui->redBox->checkState() != 0)
mask = mask | 0x00ff0000;
if (ui->greenBox->checkState() != 0)
mask = mask | 0x0000ff00;
if (ui->blueBox->checkState() != 0)
mask = mask | 0x000000ff;
if (ui->alphaBox->checkState() != 0)
mask = mask | 0xff000000;
for (int y = rect.top(); y < rect.bottom(); y)
{
uint* input = (uint*)img->scanLine(y - rect.top());
uint* output = (uint*)result->scanLine(y - rect.top());
for (int x = rect.left(); x < rect.right(); x)
{
*output = *input & mask;
output;
input+;
}
}
// At this point result will have the modified QImage