Task 773: .VDA File Format
Task 773: .VDA File Format
File Format Specifications for the .VDA File Format
The .VDA file format is a variant extension for the Truevision TARGA (TGA) raster image format, originally developed by Truevision Inc. for their TARGA and VISTA graphics cards. It supports uncompressed or run-length encoded (RLE) bitmap images with 1 to 32 bits per pixel, including support for color maps, RGB, and RGBA. The format is binary, with an 18-byte header followed by optional image ID, color map data, image data, and (in newer versions) extension areas. The specifications are based on the Truevision TGA File Format Specification 2.0, where .vda is one of the recognized extension variants (along with .tga, .icb, .vst, .pix).
- List of All Properties of This File Format Intrinsic to Its Format
The properties are the fields in the 18-byte header, which define the image structure. These are the core intrinsic properties:
- ID Length: Length of the optional image ID field (1 byte, value 0-255).
- Color Map Type: Indicates if a color map is present (1 byte, 0 = no color map, 1 = color map present).
- Image Type: Defines the image data type and compression (1 byte, e.g., 2 = uncompressed RGB, 10 = RLE RGB).
- Color Map Origin: Starting index in the color map (2 bytes, little-endian).
- Color Map Length: Number of entries in the color map (2 bytes, little-endian).
- Color Map Depth: Bits per color map entry (1 byte, e.g., 15, 16, 24, 32).
- X Origin: Horizontal origin of the image (2 bytes, little-endian, usually 0).
- Y Origin: Vertical origin of the image (2 bytes, little-endian, usually 0).
- Width: Image width in pixels (2 bytes, little-endian).
- Height: Image height in pixels (2 bytes, little-endian).
- Bits Per Pixel: Bits per pixel, including alpha (1 byte, e.g., 24 for RGB, 32 for RGBA).
- Image Descriptor: Bit flags for attribute bits, screen origin, and interleaving (1 byte; bits 0-3: attribute bits, bit 5: origin top/bottom, bits 6-7: reserved).
- Two Direct Download Links for Files of Format .VDA
.VDA files are rare, as the format is identical to .TGA but with a different extension. The following are direct links to .TGA files, which can be downloaded and renamed to .vda (the format is the same):
- https://people.math.sc.edu/Burkardt/data/tga/aspen.tga
- https://people.math.sc.edu/Burkardt/data/tga/earth.tga
- Ghost Blog Embedded HTML JavaScript for Drag and Drop .VDA File Dump
Drag and drop .VDA file here
- Python Class for .VDA File
import struct
import os
class VDAFile:
def __init__(self, filename):
self.filename = filename
self.properties = {}
def read(self):
with open(self.filename, 'rb') as f:
header = f.read(18)
if len(header) < 18:
raise ValueError("Invalid .VDA file header")
self.properties = {
'ID Length': struct.unpack('<B', header[0:1])[0],
'Color Map Type': struct.unpack('<B', header[1:2])[0],
'Image Type': struct.unpack('<B', header[2:3])[0],
'Color Map Origin': struct.unpack('<H', header[3:5])[0],
'Color Map Length': struct.unpack('<H', header[5:7])[0],
'Color Map Depth': struct.unpack('<B', header[7:8])[0],
'X Origin': struct.unpack('<H', header[8:10])[0],
'Y Origin': struct.unpack('<H', header[10:12])[0],
'Width': struct.unpack('<H', header[12:14])[0],
'Height': struct.unpack('<H', header[14:16])[0],
'Bits Per Pixel': struct.unpack('<B', header[16:17])[0],
'Image Descriptor': struct.unpack('<B', header[17:18])[0]
}
def print_properties(self):
for key, value in self.properties.items():
print(f"{key}: {value}")
def write(self, new_filename, properties, image_data=b''):
header = struct.pack('<BBBHBBHHHBB',
properties.get('ID Length', 0),
properties.get('Color Map Type', 0),
properties.get('Image Type', 2),
properties.get('Color Map Origin', 0),
properties.get('Color Map Length', 0),
properties.get('Color Map Depth', 0),
properties.get('X Origin', 0),
properties.get('Y Origin', 0),
properties.get('Width', 0),
properties.get('Height', 0),
properties.get('Bits Per Pixel', 24),
properties.get('Image Descriptor', 0))
with open(new_filename, 'wb') as f:
f.write(header)
f.write(image_data) # Optional image data for full write
# Example usage
if __name__ == "__main__":
vda = VDAFile('example.vda')
vda.read()
vda.print_properties()
# To write a new file
props = {'Width': 100, 'Height': 100, 'Bits Per Pixel': 24}
vda.write('new.vda', props)
To arrive at the solution for closed-ended mathematics questions, the reasoning is structured as follows: Parse the binary header using struct.unpack with little-endian format to extract each field based on its byte position and size.
- Java Class for .VDA File
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
public class VDAFile {
private String filename;
private int idLength;
private int colorMapType;
private int imageType;
private int colorMapOrigin;
private int colorMapLength;
private int colorMapDepth;
private int xOrigin;
private int yOrigin;
private int width;
private int height;
private int bitsPerPixel;
private int imageDescriptor;
public VDAFile(String filename) {
this.filename = filename;
}
public void read() throws IOException {
try (FileInputStream fis = new FileInputStream(filename)) {
byte[] header = new byte[18];
if (fis.read(header) < 18) {
throw new IOException("Invalid .VDA file header");
}
ByteBuffer bb = ByteBuffer.wrap(header).order(ByteOrder.LITTLE_ENDIAN);
idLength = bb.get(0) & 0xFF;
colorMapType = bb.get(1) & 0xFF;
imageType = bb.get(2) & 0xFF;
colorMapOrigin = bb.getShort(3) & 0xFFFF;
colorMapLength = bb.getShort(5) & 0xFFFF;
colorMapDepth = bb.get(7) & 0xFF;
xOrigin = bb.getShort(8) & 0xFFFF;
yOrigin = bb.getShort(10) & 0xFFFF;
width = bb.getShort(12) & 0xFFFF;
height = bb.getShort(14) & 0xFFFF;
bitsPerPixel = bb.get(16) & 0xFF;
imageDescriptor = bb.get(17) & 0xFF;
}
}
public void printProperties() {
System.out.println("ID Length: " + idLength);
System.out.println("Color Map Type: " + colorMapType);
System.out.println("Image Type: " + imageType);
System.out.println("Color Map Origin: " + colorMapOrigin);
System.out.println("Color Map Length: " + colorMapLength);
System.out.println("Color Map Depth: " + colorMapDepth);
System.out.println("X Origin: " + xOrigin);
System.out.println("Y Origin: " + yOrigin);
System.out.println("Width: " + width);
System.out.println("Height: " + height);
System.out.println("Bits Per Pixel: " + bitsPerPixel);
System.out.println("Image Descriptor: " + imageDescriptor);
}
public void write(String newFilename, int newWidth, int newHeight, int newBitsPerPixel, byte[] imageData) throws IOException {
try (FileOutputStream fos = new FileOutputStream(newFilename)) {
ByteBuffer bb = ByteBuffer.allocate(18).order(ByteOrder.LITTLE_ENDIAN);
bb.put((byte) 0); // ID Length
bb.put((byte) 0); // Color Map Type
bb.put((byte) 2); // Image Type (uncompressed RGB)
bb.putShort((short) 0); // Color Map Origin
bb.putShort((short) 0); // Color Map Length
bb.put((byte) 0); // Color Map Depth
bb.putShort((short) 0); // X Origin
bb.putShort((short) 0); // Y Origin
bb.putShort((short) newWidth); // Width
bb.putShort((short) newHeight); // Height
bb.put((byte) newBitsPerPixel); // Bits Per Pixel
bb.put((byte) 0); // Image Descriptor
fos.write(bb.array());
fos.write(imageData); // Optional image data
}
}
public static void main(String[] args) throws IOException {
VDAFile vda = new VDAFile("example.vda");
vda.read();
vda.printProperties();
// To write
vda.write("new.vda", 100, 100, 24, new byte[0]);
}
}
- JavaScript Class for .VDA File
class VDAFile {
constructor(filename) {
this.filename = filename;
this.properties = {};
}
async read() {
const response = await fetch(this.filename);
const arrayBuffer = await response.arrayBuffer();
const dataView = new DataView(arrayBuffer);
this.properties = {
'ID Length': dataView.getUint8(0),
'Color Map Type': dataView.getUint8(1),
'Image Type': dataView.getUint8(2),
'Color Map Origin': dataView.getUint16(3, true),
'Color Map Length': dataView.getUint16(5, true),
'Color Map Depth': dataView.getUint8(7),
'X Origin': dataView.getUint16(8, true),
'Y Origin': dataView.getUint16(10, true),
'Width': dataView.getUint16(12, true),
'Height': dataView.getUint16(14, true),
'Bits Per Pixel': dataView.getUint8(16),
'Image Descriptor': dataView.getUint8(17)
};
}
printProperties() {
console.log(this.properties);
}
write(newFilename, properties, imageData = new Uint8Array(0)) {
const header = new Uint8Array(18);
const dataView = new DataView(header.buffer);
dataView.setUint8(0, properties.idLength || 0);
dataView.setUint8(1, properties.colorMapType || 0);
dataView.setUint8(2, properties.imageType || 2);
dataView.setUint16(3, properties.colorMapOrigin || 0, true);
dataView.setUint16(5, properties.colorMapLength || 0, true);
dataView.setUint8(7, properties.colorMapDepth || 0);
dataView.setUint16(8, properties.xOrigin || 0, true);
dataView.setUint16(10, properties.yOrigin || 0, true);
dataView.setUint16(12, properties.width || 0, true);
dataView.setUint16(14, properties.height || 0, true);
dataView.setUint8(16, properties.bitsPerPixel || 24);
dataView.setUint8(17, properties.imageDescriptor || 0);
const blob = new Blob([header, imageData]);
const url = URL.createObjectURL(blob);
const a = document.createElement('a');
a.href = url;
a.download = newFilename;
a.click();
URL.revokeObjectURL(url);
}
}
// Example usage
const vda = new VDAFile('example.vda');
vda.read().then(() => vda.printProperties());
// To write
const props = { width: 100, height: 100, bitsPerPixel: 24 };
vda.write('new.vda', props);
- C Class for .VDA File
#include <stdio.h>
#include <stdlib.h>
typedef struct {
unsigned char idLength;
unsigned char colorMapType;
unsigned char imageType;
unsigned short colorMapOrigin;
unsigned short colorMapLength;
unsigned char colorMapDepth;
unsigned short xOrigin;
unsigned short yOrigin;
unsigned short width;
unsigned short height;
unsigned char bitsPerPixel;
unsigned char imageDescriptor;
} VDAProperties;
struct VDAFile {
char* filename;
VDAProperties properties;
};
struct VDAFile* createVDAFile(const char* filename) {
struct VDAFile* vda = malloc(sizeof(struct VDAFile));
vda->filename = (char*)filename;
return vda;
}
void readVDA(struct VDAFile* vda) {
FILE* file = fopen(vda->filename, "rb");
if (file == NULL) {
perror("Error opening file");
return;
}
unsigned char header[18];
if (fread(header, 1, 18, file) < 18) {
fprintf(stderr, "Invalid .VDA file header\n");
fclose(file);
return;
}
vda->properties.idLength = header[0];
vda->properties.colorMapType = header[1];
vda->properties.imageType = header[2];
vda->properties.colorMapOrigin = header[3] | (header[4] << 8);
vda->properties.colorMapLength = header[5] | (header[6] << 8);
vda->properties.colorMapDepth = header[7];
vda->properties.xOrigin = header[8] | (header[9] << 8);
vda->properties.yOrigin = header[10] | (header[11] << 8);
vda->properties.width = header[12] | (header[13] << 8);
vda->properties.height = header[14] | (header[15] << 8);
vda->properties.bitsPerPixel = header[16];
vda->properties.imageDescriptor = header[17];
fclose(file);
}
void printProperties(VDAProperties props) {
printf("ID Length: %u\n", props.idLength);
printf("Color Map Type: %u\n", props.colorMapType);
printf("Image Type: %u\n", props.imageType);
printf("Color Map Origin: %u\n", props.colorMapOrigin);
printf("Color Map Length: %u\n", props.colorMapLength);
printf("Color Map Depth: %u\n", props.colorMapDepth);
printf("X Origin: %u\n", props.xOrigin);
printf("Y Origin: %u\n", props.yOrigin);
printf("Width: %u\n", props.width);
printf("Height: %u\n", props.height);
printf("Bits Per Pixel: %u\n", props.bitsPerPixel);
printf("Image Descriptor: %u\n", props.imageDescriptor);
}
void writeVDA(const char* newFilename, VDAProperties props, const unsigned char* imageData, size_t dataSize) {
FILE* file = fopen(newFilename, "wb");
if (file == NULL) {
perror("Error opening file");
return;
}
unsigned char header[18] = {0};
header[0] = props.idLength;
header[1] = props.colorMapType;
header[2] = props.imageType;
header[3] = props.colorMapOrigin & 0xFF;
header[4] = (props.colorMapOrigin >> 8) & 0xFF;
header[5] = props.colorMapLength & 0xFF;
header[6] = (props.colorMapLength >> 8) & 0xFF;
header[7] = props.colorMapDepth;
header[8] = props.xOrigin & 0xFF;
header[9] = (props.xOrigin >> 8) & 0xFF;
header[10] = props.yOrigin & 0xFF;
header[11] = (props.yOrigin >> 8) & 0xFF;
header[12] = props.width & 0xFF;
header[13] = (props.width >> 8) & 0xFF;
header[14] = props.height & 0xFF;
header[15] = (props.height >> 8) & 0xFF;
header[16] = props.bitsPerPixel;
header[17] = props.imageDescriptor;
fwrite(header, 1, 18, file);
fwrite(imageData, 1, dataSize, file);
fclose(file);
}
int main() {
struct VDAFile* vda = createVDAFile("example.vda");
readVDA(vda);
printProperties(vda->properties);
// To write
VDAProperties newProps = {0};
newProps.width = 100;
newProps.height = 100;
newProps.bitsPerPixel = 24;
newProps.imageType = 2;
writeVDA("new.vda", newProps, NULL, 0);
free(vda);
return 0;
}