api(IB)!: Add span based ImageBuf methods for getpixel/setpixel

CMakeLists.txt

@@ -4,7 +4,7 @@
 
 cmake_minimum_required (VERSION 3.15)
 
-set (OpenImageIO_VERSION "2.6.6.0")
+set (OpenImageIO_VERSION "2.6.7.0")
 set (OpenImageIO_VERSION_OVERRIDE "" CACHE STRING
      "Version override (use with caution)!")
 mark_as_advanced (OpenImageIO_VERSION_OVERRIDE)

src/doc/imagebuf.rst

@@ -163,10 +163,10 @@ Getting and setting pixel values
 .. doxygenfunction:: OIIO::ImageBuf::getchannel
 .. doxygenfunction:: OIIO::ImageBuf::getpixel(int x, int y, int z, float *pixel, int maxchannels = 1000, WrapMode wrap = WrapBlack) const
 
-.. doxygenfunction:: OIIO::ImageBuf::interppixel
-.. doxygenfunction:: OIIO::ImageBuf::interppixel_bicubic
-.. doxygenfunction:: OIIO::ImageBuf::interppixel_NDC
-.. doxygenfunction:: OIIO::ImageBuf::interppixel_bicubic_NDC
+.. doxygenfunction:: OIIO::ImageBuf::interppixel(float, float, span<float>, WrapMode) const
+.. doxygenfunction:: OIIO::ImageBuf::interppixel_bicubic(float, float, span<float>, WrapMode) const
+.. doxygenfunction:: OIIO::ImageBuf::interppixel_NDC(float, float, span<float>, WrapMode) const
+.. doxygenfunction:: OIIO::ImageBuf::interppixel_bicubic_NDC(float, float, span<float>, WrapMode) const
 
 .. doxygenfunction:: OIIO::ImageBuf::setpixel(int x, int y, int z, cspan<float> pixel)
 .. doxygenfunction:: OIIO::ImageBuf::setpixel(int i, cspan<float> pixel)
@@ -175,8 +175,10 @@ Getting and setting pixel values
 
 **Getting and setting regions of pixels -- fast**
 
-.. doxygenfunction:: OIIO::ImageBuf::get_pixels
-.. doxygenfunction:: OIIO::ImageBuf::set_pixels
+.. doxygenfunction:: OIIO::ImageBuf::get_pixels(ROI, span<T>, stride_t, stride_t, stride_t) const
+.. doxygenfunction:: OIIO::ImageBuf::get_pixels(ROI, span<T>, T*, stride_t, stride_t, stride_t) const
+.. doxygenfunction:: OIIO::ImageBuf::set_pixels(ROI, span<T>, stride_t, stride_t, stride_t)
+.. doxygenfunction:: OIIO::ImageBuf::set_pixels(ROI, span<T>, const T*, stride_t, stride_t, stride_t)
 
 
 

src/include/OpenImageIO/imageio.h

@@ -3370,6 +3370,19 @@ OIIO_API bool copy_image (int nchannels, int width, int height, int depth,
                           void *dst, stride_t dst_xstride,
                           stride_t dst_ystride, stride_t dst_zstride);
 
+/// Helper: manufacture a span given an image pointer, format, size, and
+/// strides. Use with caution! This is making a lot of assumptions that the
+/// data pointer really does point to memory that's ok to access according to
+/// the sizes and strides you give.
+OIIO_API span<std::byte>
+span_from_buffer(void* data, TypeDesc format, int nchannels, int width,
+                 int height, int depth, stride_t xstride = AutoStride, stride_t ystride = AutoStride,
+                 stride_t zstride = AutoStride);
+OIIO_API cspan<std::byte>
+cspan_from_buffer(const void* data, TypeDesc format, int nchannels, int width,
+                 int height, int depth, stride_t xstride = AutoStride, stride_t ystride = AutoStride,
+                 stride_t zstride = AutoStride);
+
 
 // All the wrap_foo functions implement a wrap mode, wherein coord is
 // altered to be origin <= coord < origin+width.  The return value

src/include/OpenImageIO/span.h

@@ -558,6 +558,35 @@ spanzero(span<T> dst, size_t offset = 0, size_t n = size_t(-1))
 }
 
 
+
+/// Does the byte span `query` lie entirely within the safe `bounds` span?
+inline bool
+span_within(cspan<std::byte> bounds, cspan<std::byte> query)
+{
+    return query.data() >= bounds.data()
+           && query.data() + query.size() <= bounds.data() + bounds.size();
+}
+
+
+
+/// Verify the `ptr[0..len-1]` lies entirely within the given span `s`, which
+/// does not need to be the same data type.  Return true if that is the case,
+/// false if it extends beyond the safe limits fo the span.
+template<typename SpanType, typename PtrType>
+inline bool
+check_span(span<SpanType> s, const PtrType* ptr, size_t len = 1)
+{
+    return span_within(as_bytes(s), as_bytes(make_cspan(ptr, len)));
+}
+
+
+
+/// OIIO_ALLOCASPAN is used to allocate smallish amount of memory on the
+/// stack, equivalent of C99 type var_name[size], and then return a span
+/// encompassing it.
+#define OIIO_ALLOCA_SPAN(type, size) span<type>(OIIO_ALLOCA(type, size), size)
+
+
 OIIO_NAMESPACE_END
 
 

src/iv/imageviewer.h

@@ -116,7 +116,7 @@ class IvImage final : public ImageBuf {
     /// color space correction when indicated.
     void pixel_transform(bool srgb_to_linear, int color_mode, int channel);
 
-    bool get_pixels(ROI roi, TypeDesc format, void* result)
+    bool get_pixels(ROI roi, TypeDesc format, span<std::byte> result)
     {
         if (m_corrected_image.localpixels())
             return m_corrected_image.get_pixels(roi, format, result);

src/iv/ivgl.cpp

@@ -785,9 +785,10 @@ IvGL::paint_pixelview()
                                      m_viewer.current_color_mode());
         }
 
-        void* zoombuffer = OIIO_ALLOCA(char, (xend - xbegin) * (yend - ybegin)
-                                                 * nchannels
-                                                 * spec.channel_bytes());
+        auto zoombuffer = OIIO_ALLOCA_SPAN(std::byte,
+                                           (xend - xbegin) * (yend - ybegin)
+                                               * nchannels
+                                               * spec.channel_bytes());
         if (!m_use_shaders) {
             img->get_pixels(ROI(spec.x + xbegin, spec.x + xend, spec.y + ybegin,
                                 spec.y + yend),
@@ -805,7 +806,7 @@ IvGL::paint_pixelview()
         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
         glBindTexture(GL_TEXTURE_2D, m_pixelview_tex);
         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, xend - xbegin, yend - ybegin,
-                        glformat, gltype, zoombuffer);
+                        glformat, gltype, zoombuffer.data());
         print_error("After tsi2d");
     } else {
         smin = -1;
@@ -1527,12 +1528,14 @@ IvGL::load_texture(int x, int y, int width, int height)
     // may not be resident at once.
     if (!m_use_shaders) {
         m_current_image->get_pixels(ROI(x, x + width, y, y + height),
-                                    spec.format, &m_tex_buffer[0]);
+                                    spec.format,
+                                    as_writable_bytes(make_span(m_tex_buffer)));
     } else {
         m_current_image->get_pixels(ROI(x, x + width, y, y + height, 0, 1,
                                         m_viewer.current_channel(),
                                         m_viewer.current_channel() + nchannels),
-                                    spec.format, &m_tex_buffer[0]);
+                                    spec.format,
+                                    as_writable_bytes(make_span(m_tex_buffer)));
     }
 
     glBindBuffer(GL_PIXEL_UNPACK_BUFFER, m_pbo_objects[m_last_pbo_used]);