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Wayland: protect against rounding errors in copy_region()

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This commit is contained in:
ManoloFLTK 2024-11-09 13:01:45 +01:00
parent 5d0fcc5f15
commit 85c23539fd
1 changed files with 10 additions and 6 deletions
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16
src/drivers/Wayland/Fl_Wayland_Graphics_Driver.cxx
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@ -141,16 +141,20 @@ const struct wl_callback_listener *Fl_Wayland_Graphics_Driver::p_surface_frame_l
// copy pixels in region r from the Cairo surface to the Wayland buffer
static void copy_region(struct wld_window *window, cairo_region_t *r) {
struct Fl_Wayland_Graphics_Driver::wld_buffer *buffer = window->buffer;
float f = Fl::screen_scale(window->fl_win->screen_num()) *
Fl_Wayland_Window_Driver::driver(window->fl_win)->wld_scale();
float f = Fl::screen_scale(window->fl_win->screen_num());
int d = Fl_Wayland_Window_Driver::driver(window->fl_win)->wld_scale();
int count = cairo_region_num_rectangles(r);
cairo_rectangle_int_t rect;
for (int i = 0; i < count; i++) {
cairo_region_get_rectangle(r, i, &rect);
int left = rect.x * f;
int top = rect.y * f;
int width = ceil((rect.x + rect.width)*f) - left;
int height = ceil((rect.y + rect.height)*f) - top;
int left = d * int(rect.x * f);
int top = d * int(rect.y * f);
int right = d * ceil((rect.x + rect.width) * f);
if (right > d * int(window->fl_win->w() * f)) right = d * int(window->fl_win->w() * f);
int width = right - left;
int bottom = d * ceil((rect.y + rect.height) * f);
if (bottom > d * int(window->fl_win->h() * f)) bottom = d * int(window->fl_win->h() * f);
int height = bottom - top;
int offset = top * buffer->draw_buffer.stride + 4 * left;
int W4 = 4 * width;
for (int l = 0; l < height; l++) {