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SF.net SVN: matplotlib:[7028] branches/v0_98_5_maint/src/_png.cpp
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From: <as...@us...> - 2009-04-05 22:07:02
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Revision: 7028
http://matplotlib.svn.sourceforge.net/matplotlib/?rev=7028&view=rev
Author: astraw
Date: 2009-04-05 22:07:01 +0000 (Sun, 05 Apr 2009)
Log Message:
-----------
read 12 bit PNGs (patch from Tobias Wood)
Modified Paths:
--------------
branches/v0_98_5_maint/src/_png.cpp
Modified: branches/v0_98_5_maint/src/_png.cpp
===================================================================
--- branches/v0_98_5_maint/src/_png.cpp 2009-04-05 22:06:05 UTC (rev 7027)
+++ branches/v0_98_5_maint/src/_png.cpp 2009-04-05 22:07:01 UTC (rev 7028)
@@ -208,38 +208,37 @@
png_init_io(png_ptr, fp);
png_set_sig_bytes(png_ptr, 8);
-
png_read_info(png_ptr, info_ptr);
png_uint_32 width = info_ptr->width;
png_uint_32 height = info_ptr->height;
- bool do_gray_conversion = (info_ptr->bit_depth < 8 &&
- info_ptr->color_type == PNG_COLOR_TYPE_GRAY);
int bit_depth = info_ptr->bit_depth;
- if (bit_depth == 16) {
- png_set_strip_16(png_ptr);
- } else if (bit_depth < 8) {
+
+ // Unpack 1, 2, and 4-bit images
+ if (bit_depth < 8)
png_set_packing(png_ptr);
- }
- // convert misc color types to rgb for simplicity
- if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY ||
- info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
- png_set_gray_to_rgb(png_ptr);
- } else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) {
+ // If sig bits are set, shift data
+ png_color_8p sig_bit;
+ if ((info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) && png_get_sBIT(png_ptr, info_ptr, &sig_bit))
+ png_set_shift(png_ptr, sig_bit);
+
+ // Convert big endian to little
+ if (bit_depth == 16)
+ png_set_swap(png_ptr);
+
+ // Convert palletes to full RGB
+ if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
png_set_palette_to_rgb(png_ptr);
- }
+
+ // If there's an alpha channel convert gray to RGB
+ if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ png_set_gray_to_rgb(png_ptr);
png_set_interlace_handling(png_ptr);
png_read_update_info(png_ptr, info_ptr);
- bool rgba = info_ptr->color_type == PNG_COLOR_TYPE_RGBA;
- if ( (info_ptr->color_type != PNG_COLOR_TYPE_RGB) && !rgba) {
- std::cerr << "Found color type " << (int)info_ptr->color_type << std::endl;
- throw Py::RuntimeError("_image_module::readpng: cannot handle color_type");
- }
-
/* read file */
if (setjmp(png_jmpbuf(png_ptr)))
throw Py::RuntimeError("_image_module::readpng: error during read_image");
@@ -255,37 +254,36 @@
npy_intp dimensions[3];
dimensions[0] = height; //numrows
dimensions[1] = width; //numcols
- dimensions[2] = 4;
+ if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+ dimensions[2] = 4; //RGBA images
+ else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
+ dimensions[2] = 3; //RGB images
+ else
+ dimensions[2] = 1; //Greyscale images
+ //For gray, return an x by y array, not an x by y by 1
+ int num_dims = (info_ptr->color_type & PNG_COLOR_MASK_COLOR) ? 3 : 2;
+
+ double max_value = (1 << ((bit_depth < 8) ? 8 : bit_depth)) - 1;
+ PyArrayObject *A = (PyArrayObject *) PyArray_SimpleNew(num_dims, dimensions, PyArray_FLOAT);
- PyArrayObject *A = (PyArrayObject *) PyArray_SimpleNew(3, dimensions, PyArray_FLOAT);
-
- if (do_gray_conversion) {
- float max_value = (float)((1L << bit_depth) - 1);
- for (png_uint_32 y = 0; y < height; y++) {
- png_byte* row = row_pointers[y];
- for (png_uint_32 x = 0; x < width; x++) {
- float value = row[x] / max_value;
- size_t offset = y*A->strides[0] + x*A->strides[1];
- *(float*)(A->data + offset + 0*A->strides[2]) = value;
- *(float*)(A->data + offset + 1*A->strides[2]) = value;
- *(float*)(A->data + offset + 2*A->strides[2]) = value;
- *(float*)(A->data + offset + 3*A->strides[2]) = 1.0f;
- }
+ for (png_uint_32 y = 0; y < height; y++) {
+ png_byte* row = row_pointers[y];
+ for (png_uint_32 x = 0; x < width; x++) {
+ size_t offset = y*A->strides[0] + x*A->strides[1];
+ if (bit_depth == 16) {
+ png_uint_16* ptr = &reinterpret_cast<png_uint_16*> (row)[x * dimensions[2]];
+ for (png_uint_32 p = 0; p < dimensions[2]; p++)
+ *(float*)(A->data + offset + p*A->strides[2]) = (float)(ptr[p]) / max_value;
+ } else {
+ png_byte* ptr = &(row[x * dimensions[2]]);
+ for (png_uint_32 p = 0; p < dimensions[2]; p++)
+ {
+ *(float*)(A->data + offset + p*A->strides[2]) = (float)(ptr[p]) / max_value;
+ }
+ }
}
- } else {
- for (png_uint_32 y = 0; y < height; y++) {
- png_byte* row = row_pointers[y];
- for (png_uint_32 x = 0; x < width; x++) {
- png_byte* ptr = (rgba) ? &(row[x*4]) : &(row[x*3]);
- size_t offset = y*A->strides[0] + x*A->strides[1];
- *(float*)(A->data + offset + 0*A->strides[2]) = (float)(ptr[0]/255.0);
- *(float*)(A->data + offset + 1*A->strides[2]) = (float)(ptr[1]/255.0);
- *(float*)(A->data + offset + 2*A->strides[2]) = (float)(ptr[2]/255.0);
- *(float*)(A->data + offset + 3*A->strides[2]) = rgba ? (float)(ptr[3]/255.0) : 1.0f;
- }
- }
}
-
+
//free the png memory
png_read_end(png_ptr, info_ptr);
png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);
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