Types for Display and Drawing

The following types are used as parameters and return values in functions related to display features and drawing within GlobalMapper. These types use fixed, numeric constants, which are defined here.


This type represents the different blend modes available


GM_BlendMode_None = 0

GM_BlendMode_Multiple = 1

GM_BlendMode_Screen = 2

GM_BlendMode_Overlay = 3

GM_BlendMode_HardLight = 4

GM_BlendMode_ColorBurn = 5

GM_BlendMode_ColorDodge = 6

GM_BlendMode_ApplyColor = 7

GM_BlendMode_ApplyColorReverse = 8

GM_BlendMode_Darken = 9

GM_BlendMode_Lighten = 10

GM_BlendMode_Difference = 11

GM_BlendMode_Exclusion = 12

GM_BlendMode_KeepRedChannel = 13

GM_BlendMode_KeepGreenChannel = 14

GM_BlendMode_KeepBlueChannel = 15

GM_BlendMode_SpotNaturalColor = 16

view SPOT images as natural color

GM_BlendMode_PsuedoNaturalColor = 17

simple weighted average

GM_BlendMode_ColorToGrayscale = 18

convert RGB color image to grayscale in GlobalMapperInterface.h, which should match this.

GM_BlendMode_NumModes = 19


List of supported color formats for GM_DrawLayerListToMemory

GM_ColorFormat_32Bit_ABGR = 0

32-bit color (alpha, blue, green, red)

GM_ColorFormat_32Bit_ARGB = 1

32-bit color (alpha, red, green, blue)

GM_ColorFormat_16Bit_565 = 2

16-bit color (5 bits red, 6 bits green, 5 bits blue)

GM_ColorFormat_24Bit_BGR = 3

24-bit color (blue, green, red)

GM_ColorFormat_24Bit_RGB = 4

24-bit color (red, green, blue)

GM_ColorFormat_NumFormats = 5


This type represents the different contrast adjustment modes that are available


GM_Contrast_None = 0

GM_Contrast_PercentageStretch = 1

Stretch within some std-dev of mean to 0-255 range

GM_Contrast_RangeStretch = 2

Stretch entire valid range to 0-255 range

GM_Contrast_NumModes = 3

GM_Contrast_DefaultAuto = GM_Contrast_PercentageStretch


This type represents flags available for custom shaders

GM_CustomShader_DontBlend = 0x00000001

Don’t blend colors between elevation values

GM_CustomShader_StretchToRange = 0x00000002

Stretch custom shader to cover valid elevation range

GM_CustomShader_ShadeSlopes = 0x00000004

Shade slopes of terrain rather than elevation values


Flags to control the GM_DrawLayerList and GM_DrawPackageList operations

GM_DrawFlags_BestRasterLayers = 0x00000001

Only draw the best raster layers for this zoom scale

GM_DrawFlags_BestRasterLayersHiRes = 0x00000003

Same as GM_DrawFlags_BestRasterLayers, only it shows higher resolution layers a bit sooner

GM_DrawFlags_LowResRasterLayers = 0x00000002

Only draw the lowest resolution raster layers

GM_DrawFlags_HiResRasterLayers = 0x00000004

Only draw the highest resolution raster layers

GM_DrawFlags_BestRasterChart = 0x00000005

Only draw the best raster chart (this is tuned for marine chart display)

GM_DrawFlags_EraseBackground = 0x00000100

Erase the background with the current background color (GM_SetBackgroundColor)

GM_DrawFlags_HideAreas = 0x00000200

Do not draw any area or mesh (3D model) features from vector layers

GM_DrawFlags_HideLines = 0x00000400

Do not draw any line features from vector layers

GM_DrawFlags_HidePoints = 0x00000800

Do not draw any point features from vector layers

GM_DrawFlags_SeparateVectorLayers = 0x00001000

Draw each vector separately rather than drawing all at once.

GM_DrawFlags_HideLabels = 0x00002000

Do not label any rendered features

GM_DrawFlags_DontMaintainAspectRatio = 0x00004000

GM_DrawFlags_HidePartialLabels = 0x00008000

Hide labels that are not entirely in the draw window

GM_DrawFlags_ShowRenderProgress = 0x00010000

Show render progress dialog or call progress callback if provided

GM_DrawFlags_HideExtraIconText = 0x00020000

Hide any extra text shown below road icons

GM_DrawFlags_HideNonIconRoadLabels = 0x00040000

Hide any road line labels that are not iconized

GM_DrawFlags_RenderVertices = 0x00080000

Render vertices for area and line features

GM_DrawFlags_IncrementalRender = 0x00100000

Do an incremental render so that draw progress can be seen as layers complete rendering

GM_DrawFlags_NoAutoInterpolation = 0x00200000

Disable automatic interpolation of rasters at intermediate zoom ranges (results in faster renders w/ less quality)

GM_DrawFlags_DrawMapLayoutLayers = 0x00400000

Render any map layout layers that are enabled, like elevation legend, distance scale, feature legend, margins, and north arrow

GM_DrawFlags_Hide3DFeatures = 0x00800000

Don’t draw any 3D features on the 2D map

GM_DrawFlags_NoValidBgColorPixels = 0x01000000

If set ensures that no valid pixels in the output will have the background color. This means rendered pixels that would have that color are adjusted by 1 so they don’t exactly match.

GM_DrawFlags_OnlyLoadedLayers = 0x02000000

Don’t load new maps in map catalog for this draw if set

GM_DrawFlags_HideSelFeatures = 0x04000000

Don’t draw any selected features on the 2D map

GM_DrawFlags_IgnoreTypeFilter = 0x08000000

Ignore any current draw filters and just draw all vector features (subject to ‘deleted’ flag)

GM_DrawFlags_RasterMask = 0x00000007

Mask for raster draw options


This type represents the different font background options

GM_Font_BgAuto = 0

Automatically choose transparent or opaque background (all transparent except when centered on line)

GM_Font_BgOpaque = 1

Fill label background with current background color

GM_Font_BgTransparent = 2

Make label background transparent


Display type for map catalog


GM_MapCatalog_DisplayTypePercent = 0

GM_MapCatalog_DisplayTypePixelSize = 1

GM_MapCatalog_DisplayTypeScale = 2

GM_MapCatalog_DisplayTypeScaleRange = 3

GM_MapCatalog_NumDisplayTypes = 4


Define option for map catalog

GM_MapCatalog_SetMapProjection = 0

Set the native projection of the map at the given index. Data is GM_Projection_t*

GM_MapCatalog_NumMapOpts = 1


Type defining map layout pieces that can be saved out to a bitmap file with GM_ExportMapLayoutComponent

GM_MapLayout_Scale = 0

Distance scale bar

GM_MapLayout_ElevLegend = 1

Elevation legend

GM_MapLayout_MapLegend = 2

Map legend with vector types and/or palette

GM_MapLayout_NumPieceTypes = 3


Define flags for the type of pixel translucency

GM_PixelTrans_None = 0x00

No per-pixel translucency

GM_PixelTrans_Alpha = 0x01

An alpha channel (last band in file) is present

GM_PixelTrans_AssociatedAlpha = 0x02

Alpha channel is associated (any non-zero value is opaque, used by TIFF)

GM_PixelTrans_InvalidPixels = 0x04

Has invalid pixels or areas (but not a full alpha)

GM_PixelTrans_SpecialVal = 0x08

Format has a special value or palette index that is transparent (i.e. PNG sometimes uses this)


Misc. advanced options flags used with GM_Utility.SetMiscOptionEx

GM_POS_LatLonDecimal = 0

Display/save lat/lon as dd.ddddddd <hemi> [always positive, include hemisphere indicator]

GM_POS_LatLonDMS = 1

Display/save lat/lon as dd mm ss.ss

GM_POS_LatLonDM = 2

Display/save lat/lon as dd mm.mmm


Display/save lat/lon as MGRS

GM_POS_LatLonDecimalPlain = 4

Display/save lat/lon as +/-dd.ddddddd [no hemisphere indicator, West/South are negative]


GM_POS_Default = GM_POS_LatLonDMS


List of flags for selecting a projection

GM_SelectProj_NoInterplanetaryDatums = 0x00000001

Do not display interplanetary datums in projection selection dialog


Ways to blend the intensity when using multiple light sources.








This type is OR’d with the mRotation member of the GM_PointStyle_t structure to specify symbol rotation sense.

GM_RotateSense_TopOfMap = 0x0000

Rotation is to top of map (default)

GM_RotateSense_TrueNorth = 0x1000

Rotation is relative to true north

GM_RotateSense_MagNorth = 0x2000

Rotation is relative to magnetic north

GM_RotateSense_Mask = 0xF000

GM_RotateAngle_Mask = 0x0FFF