--- title: "slint::platform::SoftwareRenderer Class" --- ```cpp class SoftwareRenderer; ``` ```cpp #include ``` **Inherits** [slint::platform::AbstractRenderer](../abstractrenderer/). Slint's software renderer. To be used as a template parameter of the [WindowAdapter](../windowadapter/). Use the [render()](./#render) function to render in a buffer ## Types - [PhysicalRegion](../softwarerenderer-physicalregion/) - [TargetPixelBuffer](../softwarerenderer-targetpixelbuffer/) ## Public Types ### `RepaintBufferType` ```cpp enum class RepaintBufferType ``` | Value | Description | | --- | --- | | `NewBuffer` | The full window is always redrawn. No attempt at partial rendering will be made. | | `ReusedBuffer` | | | `SwappedBuffers` | | This enum describes which parts of the buffer passed to the [SoftwareRenderer](./) may be re-used to speed up painting. ### `RenderingRotation` ```cpp enum class RenderingRotation ``` | Value | Description | | --- | --- | | `NoRotation` | No rotation. | | `Rotate90` | Rotate 90° to the left. | | `Rotate180` | 180° rotation (upside-down) | | `Rotate270` | Rotate 90° to the right. | This enum describes the rotation that is applied to the buffer when rendering. To be used in [set\_rendering\_rotation()](./#set_rendering_rotation) ### `DrawTextureArgs` ```cpp cbindgen_private::DrawTextureArgs using slint::platform::SoftwareRenderer::DrawTextureArgs = cbindgen_private::DrawTextureArgs ``` Representation of a texture to blend in the destination buffer. ### `DrawRectangleArgs` ```cpp cbindgen_private::DrawRectangleArgs using slint::platform::SoftwareRenderer::DrawRectangleArgs = cbindgen_private::DrawRectangleArgs ``` Arguments for draw\_rectangle. ## Public Functions ### `~SoftwareRenderer` (virtual) ```cpp slint::platform::SoftwareRenderer::~SoftwareRenderer() ``` ### `SoftwareRenderer` ```cpp slint::platform::SoftwareRenderer::SoftwareRenderer(const SoftwareRenderer &)=delete ``` ### `operator=` ```cpp SoftwareRenderer & slint::platform::SoftwareRenderer::operator=(const SoftwareRenderer &)=delete ``` ### `SoftwareRenderer` ```cpp explicit slint::platform::SoftwareRenderer::SoftwareRenderer(RepaintBufferType buffer_type) ``` Constructs a new [SoftwareRenderer](./) with the *buffer\_type* as strategy for handling the differences between rendering buffers. ### `render` ```cpp PhysicalRegion slint::platform::SoftwareRenderer::render(std::span buffer, std::size_t pixel_stride) const ``` Render the window scene into a pixel buffer The buffer must be at least as large as the associated [slint::Window](../../window/) The stride is the amount of pixels between two lines in the buffer. It is must be at least as large as the width of the window. ### `render` ```cpp PhysicalRegion slint::platform::SoftwareRenderer::render(std::span buffer, std::size_t pixel_stride) const ``` Render the window scene into an RGB 565 encoded pixel buffer The buffer must be at least as large as the associated [slint::Window](../../window/) The stride is the amount of pixels between two lines in the buffer. It is must be at least as large as the width of the window. ### `render_by_line` ```cpp PhysicalRegion slint::platform::SoftwareRenderer::render_by_line(Callback process_line_callback) const ``` Render the window scene, line by line. The provided Callback will be invoked for each line that needs to rendered. The renderer uses a cache internally and will only render the part of the window which are dirty. This function returns the physical region that was rendered considering the rotation. The callback must be an invocable with the signature (size\_t line, size\_t begin, size\_t end, auto render\_fn). It is invoked with the line number as first parameter, and the start x and end x coordinates of the line as second and third parameter. The implementation must provide a line buffer (as [std::span](https://en.cppreference.com/w/cpp/container/span)) and invoke the provided fourth parameter (render\_fn) with it, to fill it with pixels. After the line buffer is filled with pixels, your implementation is free to flush that line to the screen for display. The first template parameter (PixelType) must be specified and can be either [Rgb565Pixel](../../rgb565pixel/) or [Rgb8Pixel](../../rgb8pixel/). ### `render` ```cpp PhysicalRegion slint::platform::SoftwareRenderer::render(TargetPixelBuffer *buffer) const ``` Renders into the given [TargetPixelBuffer](../softwarerenderer-targetpixelbuffer/). **Note**: This class is still experimental - its API is subject to changes and not stabilized yet. To use the class, you must enable the `SLINT_FEATURE_EXPERIMENTAL=ON` CMake option. ### `render` ```cpp PhysicalRegion slint::platform::SoftwareRenderer::render(TargetPixelBuffer *buffer) const ``` Renders into the given [TargetPixelBuffer](../softwarerenderer-targetpixelbuffer/). **Note**: This class is still experimental - its API is subject to changes and not stabilized yet. To use the class, you must enable the `SLINT_FEATURE_EXPERIMENTAL=ON` CMake option. ### `set_rendering_rotation` ```cpp void slint::platform::SoftwareRenderer::set_rendering_rotation(RenderingRotation rotation) ``` Set how the window needs to be rotated in the buffer. This is typically used to implement screen rotation in software ### `set_dirty_region_alignment` ```cpp void slint::platform::SoftwareRenderer::set_dirty_region_alignment(uint16_t horizontal, uint16_t vertical) ``` Align dirty regions to the specified physical pixel grid. Use this for display controllers that require aligned address windows. The pixels the alignment adds are repainted, so the returned region can be sent to the display as it is. The screen dimensions must be multiples of their corresponding alignment after applying RenderingRotation; otherwise the block at the far edge is clipped to the screen and stays shorter than the alignment. Values of zero are treated as one.