Write code to decode PNG format

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Acked-by: Christophe Fergeau <cfergeau@redhat.com>

5 files changed, 278 insertions, 9 deletions

diff --git a/Makefile.am b/Makefile.am
index b35dd57..175d8f7 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -23,8 +23,8 @@ LIBS = -lversion
 
 bin_PROGRAMS = vdagent vdservice
 
-vdagent_LDADD = -lwtsapi32 -lgdi32 vdagent_rc.$(OBJEXT)
-vdagent_CXXFLAGS = $(AM_CXXFLAGS)
+vdagent_LDADD = $(LIBPNG_LIBS) $(ZLIB_LIBS) -lwtsapi32 -lgdi32 vdagent_rc.$(OBJEXT)
+vdagent_CXXFLAGS = $(AM_CXXFLAGS) $(LIBPNG_CFLAGS)
 vdagent_LDFLAGS = $(AM_LDFLAGS) -Wl,--subsystem,windows
 vdagent_SOURCES =			\
 	common/vdcommon.cpp             \
@@ -44,6 +44,8 @@ vdagent_SOURCES =			\
 	vdagent/as_user.h		\
 	vdagent/image.cpp		\
 	vdagent/image.h			\
+	vdagent/imagepng.cpp		\
+	vdagent/imagepng.h		\
 	$(NULL)
 
 vdagent_rc.$(OBJEXT): vdagent/vdagent.rc
diff --git a/configure.ac b/configure.ac
index 4eac4b4..bb33075 100644
--- a/configure.ac
+++ b/configure.ac
@@ -101,6 +101,9 @@ dnl ---------------------------------------------------------------------------
 dnl - Check library dependencies
 dnl ---------------------------------------------------------------------------
 
+PKG_CHECK_MODULES(LIBPNG, [libpng])
+PKG_CHECK_MODULES(ZLIB, [zlib])
+
 dnl ---------------------------------------------------------------------------
 dnl - Makefiles, etc.
 dnl ---------------------------------------------------------------------------
diff --git a/vdagent/image.cpp b/vdagent/image.cpp
index faec18f..82cfb0e 100644
--- a/vdagent/image.cpp
+++ b/vdagent/image.cpp
@@ -21,9 +21,9 @@
 
 #include "vdcommon.h"
 #include "image.h"
+#include "imagepng.h"
 
 ImageCoder *create_bitmap_coder();
-ImageCoder *create_png_coder();
 
 static ImageCoder *get_coder(uint32_t vdagent_type)
 {
@@ -172,9 +172,3 @@ ImageCoder *create_bitmap_coder()
 {
     return new BitmapCoder();
 }
-
-// TODO
-ImageCoder *create_png_coder()
-{
-    return NULL;
-}
diff --git a/vdagent/imagepng.cpp b/vdagent/imagepng.cpp
new file mode 100644
index 0000000..a89b7f7
--- /dev/null
+++ b/vdagent/imagepng.cpp
@@ -0,0 +1,245 @@
+/*
+   Copyright (C) 2017 Red Hat, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of
+   the License, or (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "vdcommon.h"
+
+#include <png.h>
+#include <algorithm>
+
+#include "imagepng.h"
+
+class PngCoder: public ImageCoder
+{
+public:
+    PngCoder() {};
+    size_t get_dib_size(const uint8_t *data, size_t size);
+    void get_dib_data(uint8_t *dib, const uint8_t *data, size_t size);
+    uint8_t *from_bitmap(const BITMAPINFO& info, const void *bits, long &size);
+private:
+    size_t convert_to_dib(uint8_t *out_buf, const uint8_t *data, size_t size);
+};
+
+struct ReadBufferIo {
+    const uint8_t *buf;
+    uint32_t pos, size;
+    ReadBufferIo(const uint8_t *_buf, uint32_t _size):
+        buf(_buf), pos(0), size(_size)
+    {}
+};
+
+static void read_from_bufio(png_structp png, png_bytep out, png_size_t size)
+{
+    ReadBufferIo& io(*(ReadBufferIo*)png_get_io_ptr(png));
+    if (io.pos + size > io.size)
+        png_error(png, "read past end");
+    memcpy(out, io.buf+io.pos, size);
+    io.pos += size;
+}
+
+size_t PngCoder::get_dib_size(const uint8_t *data, size_t size)
+{
+    return convert_to_dib(NULL, data, size);
+}
+
+typedef void line_fixup_t(uint8_t *line, unsigned int width);
+
+static void line_fixup_none(uint8_t *line, unsigned int width)
+{
+}
+
+static void line_fixup_2bpp_to_4bpp(uint8_t *line, unsigned int width)
+{
+    width = (width + 3) / 4u;
+    while (width--) {
+        uint8_t from = line[width];
+        line[width*2+1] = ((from & 0x03) << 0) | ((from & 0x0c) << 2);
+        line[width*2+0] = ((from & 0x30) >> 4) | ((from & 0xc0) >> 2);
+    }
+}
+
+size_t PngCoder::convert_to_dib(uint8_t *out_buf, const uint8_t *data, size_t size)
+{
+    ReadBufferIo io(data, size);
+
+    png_structp png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (!png)
+        return 0;
+
+    png_infop info = png_create_info_struct(png);
+    if (!info) {
+        png_destroy_read_struct(&png, &info, NULL);
+        return 0;
+    }
+
+    if (setjmp(png_jmpbuf(png))) {
+        png_destroy_read_struct(&png, &info, NULL);
+        return 0;
+    }
+
+    png_set_read_fn(png, &io, read_from_bufio);
+
+    png_read_info(png, info);
+
+    // not so much precision is supported
+    unsigned int bits = png_get_bit_depth(png, info);
+    if (bits == 16)
+        png_set_strip_16(png);
+
+    unsigned int out_bits;
+    bool is_gray = false;
+    line_fixup_t *line_fixup = line_fixup_none;
+    switch (png_get_color_type(png, info)) {
+    case PNG_COLOR_TYPE_GRAY:
+        is_gray = true;
+        if (bits == 16) {
+            out_bits = 8;
+        } else if (bits == 2) {
+            line_fixup = line_fixup_2bpp_to_4bpp;
+            out_bits = 4;
+        } else {
+            out_bits = bits;
+        }
+        break;
+    case PNG_COLOR_TYPE_PALETTE:
+        // should return 1, 4 and 8, BMP does not support 2
+        out_bits = bits;
+        if (bits == 2) {
+            line_fixup = line_fixup_2bpp_to_4bpp;
+            out_bits = 4;
+        }
+        break;
+    case PNG_COLOR_TYPE_RGB:
+        png_set_bgr(png);
+        out_bits = 24;
+        break;
+    case PNG_COLOR_TYPE_RGB_ALPHA:
+        png_set_bgr(png);
+        out_bits = 24;
+        png_set_strip_alpha(png);
+        break;
+    case PNG_COLOR_TYPE_GRAY_ALPHA:
+        is_gray = true;
+        // gray with alpha should always be 8 bit but make it sure
+        // in case format change
+        png_set_expand_gray_1_2_4_to_8(png);
+        out_bits = 8;
+        png_set_strip_alpha(png);
+        break;
+    default:
+        png_error(png, "PNG color type not supported");
+        break;
+    }
+
+    const unsigned int width = png_get_image_width(png, info);
+    const unsigned int height = png_get_image_height(png, info);
+    const size_t stride = compute_dib_stride(width, out_bits);
+    const size_t image_size = stride * height;
+    int palette_colors;
+    // no palette
+    if (out_bits > 8) {
+        palette_colors = 0;
+    // 2 bit PNG converted to 4 bit BMP
+    } else if (bits == 2) {
+        palette_colors = 4;
+    } else {
+        palette_colors = 1 << out_bits;
+    }
+    const size_t palette_size = palette_colors * sizeof(RGBQUAD);
+    const size_t dib_size = sizeof(BITMAPINFOHEADER) + palette_size + image_size;
+
+    // just called to get the size, return the information
+    if (!out_buf) {
+        png_destroy_read_struct(&png, &info, NULL);
+        return dib_size;
+    }
+
+    // TODO tests
+    // bits, 1, 2, 4, 8, 16
+    // all color types
+    // alpha/not alpha
+    // indexed with not all colors
+
+    // fill header
+    BITMAPINFOHEADER& head(*(BITMAPINFOHEADER *)out_buf);
+    memset(&head, 0, sizeof(head));
+    head.biSize = sizeof(head);
+    head.biWidth = width;
+    head.biHeight = height;
+    head.biPlanes = 1;
+    head.biBitCount = out_bits;
+    head.biCompression = BI_RGB;
+    head.biSizeImage = image_size;
+
+    // copy palette
+    RGBQUAD *rgb = (RGBQUAD *)(out_buf + sizeof(BITMAPINFOHEADER));
+    if (is_gray) {
+        const unsigned int mult = 255 / (palette_colors - 1);
+        for (int color = 0; color < palette_colors; ++color) {
+            rgb->rgbBlue = rgb->rgbGreen = rgb->rgbRed = color * mult;
+            rgb->rgbReserved = 0;
+            ++rgb;
+        }
+        head.biClrUsed = palette_colors;
+    } else if (out_bits <= 8) {
+        png_colorp palette = NULL;
+        int num_palette;
+        if (!png_get_PLTE(png, info, &palette, &num_palette)) {
+            png_error(png, "error getting palette");
+        }
+        for (int color = 0; color < palette_colors; ++color) {
+            if (color < num_palette) {
+                rgb->rgbBlue = palette->blue;
+                rgb->rgbGreen = palette->green;
+                rgb->rgbRed = palette->red;
+            } else {
+                rgb->rgbBlue = rgb->rgbGreen = rgb->rgbRed = 0;
+            }
+            rgb->rgbReserved = 0;
+            ++rgb;
+            ++palette;
+        }
+        head.biClrUsed = palette_colors;
+    }
+
+    // now do the actual conversion!
+    uint8_t *dst = out_buf + sizeof(BITMAPINFOHEADER) + palette_size + image_size;
+    for (unsigned int row = 0; row < height; ++row) {
+        ((uint32_t*)dst)[-1] = 0; // padding
+        dst -= stride;
+        png_read_row(png, dst, NULL);
+        line_fixup(dst, width);
+    }
+
+    png_destroy_read_struct(&png, &info, NULL);
+    return dib_size;
+}
+
+void PngCoder::get_dib_data(uint8_t *dib, const uint8_t *data, size_t size)
+{
+    convert_to_dib(dib, data, size);
+}
+
+uint8_t *PngCoder::from_bitmap(const BITMAPINFO& info, const void *bits, long &size)
+{
+    // TODO not implemented
+    return NULL;
+}
+
+ImageCoder *create_png_coder()
+{
+    return new PngCoder();
+}
diff --git a/vdagent/imagepng.h b/vdagent/imagepng.h
new file mode 100644
index 0000000..1d1f654
--- /dev/null
+++ b/vdagent/imagepng.h
@@ -0,0 +1,25 @@
+/*
+   Copyright (C) 2017 Red Hat, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of
+   the License, or (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef VDAGENT_IMAGEPNG_H_
+#define VDAGENT_IMAGEPNG_H_
+
+#include "image.h"
+
+ImageCoder *create_png_coder();
+
+#endif