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Code Issues Activity Actions

ImageViewer: Change how scaling works

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- Store scale as a (float) factor (not as %)
- Make scaling exponential so that matches PixelPaint and another
image viewers/editors/etc
This commit is contained in:
Maciej 2021-12-28 11:52:15 +01:00 • committed by Andreas Kling
parent 1c3a82d59e
commit ab324c1dae
3 changed files with 23 additions and 27 deletions
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32
Userland/Applications/ImageViewer/ViewWidget.cpp
View file

@ -118,22 +118,21 @@ void ViewWidget::navigate(Directions direction)
this->load_from_file(m_files_in_same_dir.at(index));
}
void ViewWidget::set_scale(int scale)
void ViewWidget::set_scale(float scale)
{
if (m_bitmap.is_null())
return;
if (scale < 10)
scale = 10;
if (scale > 1000)
scale = 1000;
if (scale < 0.1f)
scale = 0.1f;
if (scale > 10.f)
scale = 10.f;
m_scale = scale;
float scale_factor = (float)m_scale / 100.0f;
Gfx::IntSize new_size;
new_size.set_width(m_bitmap->width() * scale_factor);
new_size.set_height(m_bitmap->height() * scale_factor);
new_size.set_width(m_bitmap->width() * m_scale);
new_size.set_height(m_bitmap->height() * m_scale);
m_bitmap_rect.set_size(new_size);
if (on_scale_change)
@ -207,19 +206,16 @@ void ViewWidget::mousemove_event(GUI::MouseEvent& event)
void ViewWidget::mousewheel_event(GUI::MouseEvent& event)
{
int new_scale = m_scale - event.wheel_delta() * 10;
if (new_scale < 10)
new_scale = 10;
if (new_scale > 1000)
new_scale = 1000;
float new_scale = m_scale / AK::exp2(event.wheel_delta() / 8.f);
if (new_scale < 0.1f)
new_scale = 0.1f;
if (new_scale > 10.f)
new_scale = 10.f;
if (new_scale == m_scale) {
return;
}
auto old_scale_factor = (float)m_scale / 100.0f;
auto new_scale_factor = (float)new_scale / 100.0f;
// focus_point is the window position the cursor is pointing to.
// The pixel (in image space) the cursor points to is located at
// (m_pan_origin + focus_point) / scale_factor.
@ -232,7 +228,7 @@ void ViewWidget::mousewheel_event(GUI::MouseEvent& event)
};
// A little algebra shows that new m_pan_origin equals to:
m_pan_origin = (m_pan_origin + focus_point) * (new_scale_factor / old_scale_factor) - focus_point;
m_pan_origin = (m_pan_origin + focus_point) * (new_scale / m_scale) - focus_point;
set_scale(new_scale);
}
@ -313,7 +309,7 @@ void ViewWidget::resize_window()
void ViewWidget::reset_view()
{
m_pan_origin = { 0, 0 };
set_scale(100);
set_scale(1.f);
}
void ViewWidget::set_bitmap(const Gfx::Bitmap* bitmap)