Add still-frame PNG image device for use by digitizers/cameras/etc. [R. Belmont]

Other formats can be added, we already have libjpeg in 3rdparty/.

scripts/src/machine.lua

@@ -57,6 +57,8 @@ files {
 	MAME_DIR .. "src/devices/imagedev/midiin.h",
 	MAME_DIR .. "src/devices/imagedev/midiout.cpp",
 	MAME_DIR .. "src/devices/imagedev/midiout.h",
+	MAME_DIR .. "src/devices/imagedev/picture.cpp",
+	MAME_DIR .. "src/devices/imagedev/picture.h",
 	MAME_DIR .. "src/devices/imagedev/printer.cpp",
 	MAME_DIR .. "src/devices/imagedev/printer.h",
 	MAME_DIR .. "src/devices/imagedev/snapquik.cpp",

src/devices/imagedev/picture.cpp

@@ -0,0 +1,64 @@
+// license:BSD-3-Clause
+// copyright-holders:R. Belmont
+/*********************************************************************
+
+    picture.cpp
+
+    Image device for still pictures.
+
+*********************************************************************/
+
+#include "emu.h"
+#include "picture.h"
+#include "png.h"
+
+/***************************************************************************
+    TYPE DEFINITIONS
+***************************************************************************/
+
+// device type definition
+DEFINE_DEVICE_TYPE(IMAGE_PICTURE, picture_image_device, "picture_image", "Still Image")
+
+//-------------------------------------------------
+//  microdrive_image_device - constructor
+//-------------------------------------------------
+
+picture_image_device::picture_image_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
+	device_t(mconfig, IMAGE_PICTURE, tag, owner, clock),
+	device_image_interface(mconfig, *this),
+	m_picture(nullptr)
+{
+}
+
+//-------------------------------------------------
+//  microdrive_image_device - destructor
+//-------------------------------------------------
+
+picture_image_device::~picture_image_device()
+{
+	if (m_picture)
+	{
+		delete m_picture;
+		m_picture = nullptr;
+	}
+}
+
+
+void picture_image_device::device_start()
+{
+}
+
+image_init_result picture_image_device::call_load()
+{
+	m_picture = new bitmap_argb32;
+	if (png_read_bitmap(image_core_file(), *m_picture) != PNGERR_NONE)
+	{
+		return image_init_result::FAIL;
+	}
+
+	return image_init_result::PASS;
+}
+
+void picture_image_device::call_unload()
+{
+}

src/devices/imagedev/picture.h

@@ -0,0 +1,58 @@
+// license:BSD-3-Clause
+// copyright-holders:R. Belmont
+/*********************************************************************
+
+    picture.h
+
+    Image device that loads still pictures (currently PNG)
+
+*********************************************************************/
+
+#ifndef MAME_DEVICES_IMAGEDEV_PICTURE_H
+#define MAME_DEVICES_IMAGEDEV_PICTURE_H
+
+#pragma once
+
+#include "bitmap.h"
+
+/***************************************************************************
+    TYPE DEFINITIONS
+***************************************************************************/
+
+// ======================> microdrive_image_device
+
+class picture_image_device : public device_t,
+								public device_image_interface
+{
+public:
+	// construction/destruction
+	picture_image_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock = 0);
+	virtual ~picture_image_device();
+
+	// image-level overrides
+	virtual image_init_result call_load() override;
+	virtual void call_unload() override;
+	virtual iodevice_t image_type() const override { return IO_PICTURE; }
+
+	virtual bool is_readable()  const override { return 1; }
+	virtual bool is_writeable() const override { return 0; }
+	virtual bool is_creatable() const override { return 0; }
+	virtual bool must_be_loaded() const override { return 0; }
+	virtual bool is_reset_on_load() const override { return 0; }
+	virtual const char *file_extensions() const override { return "png"; }
+
+	bitmap_argb32 &get_bitmap() { return *m_picture; }
+
+protected:
+	// device-level overrides
+	virtual void device_start() override;
+
+private:
+	bitmap_argb32 *m_picture;
+};
+
+
+// device type definition
+DECLARE_DEVICE_TYPE(IMAGE_PICTURE, picture_image_device)
+
+#endif // MAME_DEVICES_IMAGEDEV_PICTURE_H

src/emu/diimage.cpp

@@ -45,7 +45,8 @@ const image_device_type_info device_image_interface::m_device_info_array[] =
 		{ IO_MAGTAPE,   "magtape",      "magt" }, /* 14 */
 		{ IO_ROM,       "romimage",     "rom"  }, /* 15 */
 		{ IO_MIDIIN,    "midiin",       "min"  }, /* 16 */
-		{ IO_MIDIOUT,   "midiout",      "mout" }  /* 17 */
+		{ IO_MIDIOUT,   "midiout",      "mout" }, /* 17 */
+		{ IO_PICTURE,   "picture",      "pic"  }  /* 18 */
 	};
 
 

src/emu/diimage.h

@@ -50,7 +50,8 @@ enum iodevice_t
 	IO_ROM,         /* 16 - Individual ROM image - the Amstrad CPC has a few applications that were sold on 16kB ROMs */
 	IO_MIDIIN,      /* 17 - MIDI In port */
 	IO_MIDIOUT,     /* 18 - MIDI Out port */
-	IO_COUNT        /* 19 - Total Number of IO_devices for searching */
+	IO_PICTURE,     /* 19 - A single-frame image */
+	IO_COUNT        /* 20 - Total Number of IO_devices for searching */
 };
 
 enum image_error_t