swr: Fix panic when drawing clipped text

In some case, when the clip is, eg on a 0.25 of a pixel, but the offset is 0.75, (such that the begining of the glyph starts at 0.5) difference in rounding in different computation can result in a width which is one pixel bigger than the source image. I couldn't reproduce this in a testcase, but this can be reproduced while resizing or scrolling through a TextEdit I think this fixes #2957 The panic fixed by this commit looks like this: ``` thread 'main' panicked at 'index out of bounds: the len is 131 but the index is 131', /home/olivier/slint/internal/core/software_renderer/draw_functions.rs:81:19 stack backtrace: 3: i_slint_core::software_renderer::draw_functions::draw_texture_line at ./internal/core/software_renderer/draw_functions.rs:81:19 4: <i_slint_core::software_renderer::RenderToBuffer<T> as i_slint_core::software_renderer::ProcessScene>::process_shared_image_buffer at ./internal/core/software_renderer.rs:1023:13 5: i_slint_core::software_renderer::SceneBuilder<T>::draw_text_paragraph::{{closure}} at ./internal/core/software_renderer.rs:1404:37 6: i_slint_core::textlayout::TextParagraphLayout<Font>::layout_lines::{{closure}} at ./internal/core/textlayout.rs:219:17 ```
slint-ui · Jul 7, 2023 · 4a56531 · 4a56531
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,7 @@ All notable changes to this project are documented in this file.
 
  - Fixed compiler panics when some complex expressions are used for the model expression in `for` (#2977)
  - Native style: Fixed support for floating point ranges in Slider.
+ - Fixed panics in the software renderer related to text rendering.
 
 ### Slint Language
 

diff --git a/internal/core/software_renderer.rs b/internal/core/software_renderer.rs
@@ -1376,7 +1376,7 @@ impl<'a, T: ProcessScene> SceneBuilder<'a, T> {
                             if geometry.is_empty() {
                                 continue;
                             }
-                            let origin = (geometry.origin - offset.round()).cast::<usize>();
+                            let origin = (geometry.origin - offset.round()).round().cast::<usize>();
                             let actual_x = origin.x - src_rect.origin.x as usize;
                             let actual_y = origin.y - src_rect.origin.y as usize;
                             let stride = glyph.width.get() as u16;